merge with upcoming

asm/macros/battle_script.inc

@@ -1637,6 +1637,11 @@
 	.byte \case
 	.endm
 
+	.macro handleultraburst battler:req, case:req
+	various \battler, VARIOUS_HANDLE_ULTRA_BURST
+	.byte \case
+	.endm
+
 	.macro handleformchange battler:req, case:req
 	various \battler, VARIOUS_HANDLE_FORM_CHANGE
 	.byte \case

data/battle_anim_scripts.s

@@ -947,6 +947,7 @@ gBattleAnims_General::
 	.4byte General_ZMoveActivate            @ B_ANIM_ZMOVE_ACTIVATE
 	.4byte General_AffectionHangedOn        @ B_ANIM_AFFECTION_HANGED_ON
 	.4byte General_Snow                     @ B_ANIM_SNOW_CONTINUES
+	.4byte General_UltraBurst               @ B_ANIM_ULTRA_BURST
 
 	.align 2
 gBattleAnims_Special::
@@ -27002,6 +27003,43 @@ General_PrimalReversion_Omega:
 	blendoff
 	end
 
+General_UltraBurst::
+	loadspritegfx ANIM_TAG_ULTRA_BURST_SYMBOL
+	loadspritegfx ANIM_TAG_SPARK_2 @spark
+	loadspritegfx ANIM_TAG_LEAF @green
+	loadspritegfx ANIM_TAG_ELECTRIC_ORBS @charge particles
+	loadspritegfx ANIM_TAG_CIRCLE_OF_LIGHT @psycho boost
+	monbg ANIM_ATTACKER
+	setalpha 12, 8
+	createvisualtask AnimTask_BlendBattleAnimPal, 0xa, (F_PAL_BG | F_PAL_ADJACENT), 0x2, 0x0, 0xF, 0x0000
+	waitforvisualfinish
+	createvisualtask AnimTask_ElectricChargingParticles, 2, ANIM_ATTACKER, 60, 2, 12 	@ charge particles to attacker
+	delay 0x1e
+	loopsewithpan SE_M_CHARGE, SOUND_PAN_ATTACKER, 0xe, 0xa
+	createsprite gSuperpowerOrbSpriteTemplate, ANIM_TARGET, 3, 0x0
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	call LightThatBurnsTheSkyGreenSparks
+	delay 20
+	createvisualtask AnimTask_BlendBattleAnimPalExclude, 5, 5, 2, 0, 16, RGB_WHITEALPHA
+	createvisualtask AnimTask_TransformMon, 2, 1, 0
+	createsprite gUltraBurstSymbolSpriteTemplate, ANIM_ATTACKER, 0x0, 0x0, 0x0, 0x0, 0x0
+	waitforvisualfinish
+	createvisualtask AnimTask_BlendBattleAnimPalExclude, 5, 5, 2, 16, 0, RGB_WHITEALPHA
+	createvisualtask AnimTask_HorizontalShake, 5, ANIM_TARGET, 5, 14
+	waitforvisualfinish
+	createvisualtask SoundTask_PlayNormalCry, 0
+	waitforvisualfinish
+	clearmonbg ANIM_ATK_PARTNER
+	blendoff
+	end
+
 General_AffectionHangedOn::
 	loadspritegfx ANIM_TAG_RED_HEART
 	loopsewithpan SE_M_CHARM, SOUND_PAN_ATTACKER, 12, 3

data/battle_scripts_1.s

@@ -7796,6 +7796,21 @@ BattleScript_PrimalReversionRet::
 	switchinabilities BS_ATTACKER
 	return
 
+BattleScript_UltraBurst::
+	printstring STRINGID_EMPTYSTRING3
+	trytrainerslidezmovemsg BS_ATTACKER
+	printstring STRINGID_ULTRABURSTREACTING
+	waitmessage B_WAIT_TIME_LONG
+	setbyte gIsCriticalHit, 0
+	handleultraburst BS_ATTACKER, 0
+	playanimation BS_ATTACKER, B_ANIM_ULTRA_BURST
+	waitanimation
+	handleultraburst BS_ATTACKER, 1
+	printstring STRINGID_ULTRABURSTCOMPLETED
+	waitmessage B_WAIT_TIME_LONG
+	switchinabilities BS_ATTACKER
+	end3
+
 BattleScript_AttackerFormChange::
 	pause 5
 	copybyte gBattlerAbility, gBattlerAttacker

include/battle.h

@@ -292,6 +292,8 @@ struct AiLogicData
     s32 simulatedDmg[MAX_BATTLERS_COUNT][MAX_BATTLERS_COUNT][MAX_MON_MOVES]; // attacker, target, moveIndex
     u8 effectiveness[MAX_BATTLERS_COUNT][MAX_BATTLERS_COUNT][MAX_MON_MOVES]; // attacker, target, moveIndex
     u8 moveLimitations[MAX_BATTLERS_COUNT];
+    bool8 shouldSwitchMon; // Because all available moves have no/little effect. Each bit per battler.
+    u8 monToSwitchId[MAX_BATTLERS_COUNT]; // ID of the mon to switch.
 };
 
 struct AI_ThinkingStruct
@@ -304,8 +306,7 @@ struct AI_ThinkingStruct
     u32 aiFlags;
     u8 aiAction;
     u8 aiLogicId;
-    struct AI_SavedBattleMon saved[4];
+    struct AI_SavedBattleMon saved[MAX_BATTLERS_COUNT];
-    bool8 switchMon; // Because all available moves have no/little effect.
 };
 
 #define AI_MOVE_HISTORY_COUNT 3
@@ -488,6 +489,15 @@ struct MegaEvolutionData
     u8 triggerSpriteId;
 };
 
+struct UltraBurstData
+{
+    u8 toBurst; // As flags using gBitTable.
+    bool8 alreadyBursted[4]; // Array id is used for mon position.
+    u8 battlerId;
+    bool8 playerSelect;
+    u8 triggerSpriteId;
+};
+
 struct Illusion
 {
     u8 on;
@@ -616,6 +626,7 @@ struct BattleStruct
     u8 abilityPopUpSpriteIds[MAX_BATTLERS_COUNT][2];    // two per battler
     bool8 throwingPokeBall;
     struct MegaEvolutionData mega;
+    struct UltraBurstData burst;
     struct ZMoveData zmove;
     const u8 *trainerSlideMsg;
     bool8 trainerSlideLowHpMsgDone;

include/battle_controllers.h

@@ -99,6 +99,7 @@ enum {
 // Special return values in gBattleBufferB from Battle Controller functions.
 #define RET_VALUE_LEVELED_UP   11
 #define RET_MEGA_EVOLUTION 0x80
+#define RET_ULTRA_BURST 0x70
 
 struct UnusedControllerStruct
 {
@@ -129,6 +130,7 @@ struct ChooseMoveStruct
     u8 monType2;
     u8 monType3;
     struct MegaEvolutionData mega;
+    struct UltraBurstData burst;
     struct ZMoveData zmove;
 };
 

include/battle_interface.h

@@ -53,11 +53,13 @@ enum
 #define TAG_ALPHA_INDICATOR_TILE        0xD779
 #define TAG_OMEGA_INDICATOR_TILE        0xD77A
 #define TAG_ZMOVE_TRIGGER_TILE          0xD77B
+#define TAG_BURST_TRIGGER_TILE          0xD77C
 
 #define TAG_MEGA_TRIGGER_PAL            0xD777
 #define TAG_MEGA_INDICATOR_PAL          0xD778
 #define TAG_ALPHA_OMEGA_INDICATOR_PAL   0xD779 // Alpha and Omega indicators use the same palette as each of them only uses 4 different colors.
 #define TAG_ZMOVE_TRIGGER_PAL           0xD77B
+#define TAG_BURST_TRIGGER_PAL           0xD77C
 
 enum
 {
@@ -91,6 +93,11 @@ void CreateMegaTriggerSprite(u8 battlerId, u8 palId);
 bool32 IsMegaTriggerSpriteActive(void);
 void HideMegaTriggerSprite(void);
 void DestroyMegaTriggerSprite(void);
+void ChangeBurstTriggerSprite(u8 spriteId, u8 animId);
+void CreateBurstTriggerSprite(u8 battlerId, u8 palId);
+bool32 IsBurstTriggerSpriteActive(void);
+void HideBurstTriggerSprite(void);
+void DestroyBurstTriggerSprite(void);
 void MegaIndicator_LoadSpritesGfx(void);
 u8 CreatePartyStatusSummarySprites(u8 battler, struct HpAndStatus *partyInfo, bool8 skipPlayer, bool8 isBattleStart);
 void Task_HidePartyStatusSummary(u8 taskId);

include/battle_scripts.h

@@ -472,6 +472,7 @@ extern const u8 BattleScript_SpikesActivates[];
 extern const u8 BattleScript_BerserkGeneRet[];
 extern const u8 BattleScript_TargetFormChangeWithStringNoPopup[];
 extern const u8 BattleScript_DefDown[];
+extern const u8 BattleScript_UltraBurst[];
 
 // zmoves
 extern const u8 BattleScript_ZMoveActivateDamaging[];

include/battle_util.h

@@ -177,8 +177,10 @@ uq4_12_t GetTypeModifier(u8 atkType, u8 defType);
 s32 GetStealthHazardDamage(u8 hazardType, u8 battler);
 s32 GetStealthHazardDamageByTypesAndHP(u8 hazardType, u8 type1, u8 type2, u32 maxHp);
 bool32 CanMegaEvolve(u8 battler);
+bool32 CanUltraBurst(u8 battler);
 bool32 IsBattlerMegaEvolved(u8 battler);
 bool32 IsBattlerPrimalReverted(u8 battler);
+bool32 IsBattlerUltraBursted(u8 battler);
 u16 GetBattleFormChangeTargetSpecies(u8 battler, u16 method);
 bool32 TryBattleFormChange(u8 battler, u16 method);
 bool32 DoBattlersShareType(u32 battler1, u32 battler2);

include/constants/battle.h

@@ -495,4 +495,9 @@
 #define PARENTAL_BOND_2ND_HIT 1
 #define PARENTAL_BOND_OFF     0
 
+// Constants for if HandleScriptMegaPrimalBurst should handle Mega Evolution, Primal Reversion, or Ultra Burst.
+#define HANDLE_TYPE_MEGA_EVOLUTION 0
+#define HANDLE_TYPE_PRIMAL_REVERSION 1
+#define HANDLE_TYPE_ULTRA_BURST 2
+
 #endif // GUARD_CONSTANTS_BATTLE_H

include/constants/battle_anim.h

@@ -548,6 +548,7 @@
 #define B_ANIM_ZMOVE_ACTIVATE           34 // Using Z Moves
 #define B_ANIM_AFFECTION_HANGED_ON      35
 #define B_ANIM_SNOW_CONTINUES           36
+#define B_ANIM_ULTRA_BURST              37
 
 // special animations table (gBattleAnims_Special)
 #define B_ANIM_LVL_UP                   0

include/constants/battle_script_commands.h

@@ -257,6 +257,7 @@
 #define VARIOUS_TRY_REVIVAL_BLESSING                 165
 #define VARIOUS_TRY_TRAINER_SLIDE_MSG_Z_MOVE         166
 #define VARIOUS_TRY_TRAINER_SLIDE_MSG_MEGA_EVOLUTION 167
+#define VARIOUS_HANDLE_ULTRA_BURST                   168
 
 // Cmd_manipulatedamage
 #define DMG_CHANGE_SIGN            0

include/constants/battle_string_ids.h

@@ -665,8 +665,10 @@
 #define STRINGID_SNOWSTOPPED                          663
 #define STRINGID_SNOWWARNINGSNOW                      664
 #define STRINGID_PKMNITEMMELTED                       665
+#define STRINGID_ULTRABURSTREACTING                   666
+#define STRINGID_ULTRABURSTCOMPLETED                  667
 
-#define BATTLESTRINGS_COUNT                           666
+#define BATTLESTRINGS_COUNT                           668
 
 // This is the string id that gBattleStringsTable starts with.
 // String ids before this (e.g. STRINGID_INTROMSG) are not in the table,

include/constants/form_change_types.h

@@ -96,4 +96,9 @@
 // param1: ability to check.
 #define FORM_CHANGE_BATTLE_TURN_END             15
 
+// Form change that activates when the mon has the defined item.
+// If it's on the player's side, it also requires for the player to trigger it by pressing START before selecting a move.
+// param1: item to hold.
+#define FORM_CHANGE_BATTLE_ULTRA_BURST          16
+
 #endif // GUARD_CONSTANTS_FORM_CHANGE_TYPES_H

include/constants/pokemon.h

@@ -325,6 +325,7 @@
 #define SPECIES_FLAG_HISUIAN_FORM       (1 << 7)
 #define SPECIES_FLAG_ALL_PERFECT_IVS    (1 << 8)
 #define SPECIES_FLAG_CANNOT_BE_TRADED   (1 << 9)
+#define SPECIES_FLAG_ULTRA_BURST        (1 << 10)
 
 #define LEGENDARY_PERFECT_IV_COUNT 3
 

include/test/battle.h

@@ -796,6 +796,8 @@ struct MoveContext
     u16 explicitSecondaryEffect:1;
     u16 megaEvolve:1;
     u16 explicitMegaEvolve:1;
+    u16 ultraBurst:1;
+    u16 explicitUltraBurst:1;
     // TODO: u8 zMove:1;
     u16 allowed:1;
     u16 explicitAllowed:1;

src/battle_ai_main.c

@@ -403,6 +403,78 @@ void GetAiLogicData(void)
     }
 }
 
+static bool32 AI_SwitchMonIfSuitable(u32 battler)
+{
+    u32 monToSwitchId = GetMostSuitableMonToSwitchInto(battler);
+    if (monToSwitchId != PARTY_SIZE)
+    {
+        AI_DATA->shouldSwitchMon |= gBitTable[battler];
+        AI_DATA->monToSwitchId[battler] = monToSwitchId;
+        return TRUE;
+    }
+    return FALSE;
+}
+
+static bool32 AI_ShouldSwitchIfBadMoves(u32 battler, bool32 doubleBattle)
+{
+    u32 i, j;
+    // If can switch.
+    if (CountUsablePartyMons(battler) > 0
+        && !IsBattlerTrapped(battler, TRUE)
+        && !(gBattleTypeFlags & (BATTLE_TYPE_ARENA | BATTLE_TYPE_PALACE))
+        && AI_THINKING_STRUCT->aiFlags & (AI_FLAG_CHECK_VIABILITY | AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_TRY_TO_FAINT | AI_FLAG_PREFER_BATON_PASS))
+    {
+        // Consider switching if all moves are worthless to use.
+        if (GetTotalBaseStat(gBattleMons[battler].species) >= 310 // Mon is not weak.
+            && gBattleMons[battler].hp >= gBattleMons[battler].maxHP / 2) // Mon has more than 50% of its HP
+        {
+            s32 cap = AI_THINKING_STRUCT->aiFlags & (AI_FLAG_CHECK_VIABILITY) ? 95 : 93;
+            if (doubleBattle)
+            {
+                for (i = 0; i < MAX_BATTLERS_COUNT; i++)
+                {
+                    if (i != battler && IsBattlerAlive(i))
+                    {
+                        for (j = 0; j < MAX_MON_MOVES; j++)
+                        {
+                            if (gBattleStruct->aiFinalScore[battler][i][j] > cap)
+                                break;
+                        }
+                        if (j != MAX_MON_MOVES)
+                            break;
+                    }
+                }
+                if (i == MAX_BATTLERS_COUNT && AI_SwitchMonIfSuitable(battler))
+                    return TRUE;
+            }
+            else
+            {
+                for (i = 0; i < MAX_MON_MOVES; i++)
+                {
+                    if (AI_THINKING_STRUCT->score[i] > cap)
+                        break;
+                }
+
+                if (i == MAX_MON_MOVES && AI_SwitchMonIfSuitable(battler))
+                    return TRUE;
+            }
+
+        }
+
+        // Consider switching if your mon with truant is bodied by Protect spam.
+        // Or is using a double turn semi invulnerable move(such as Fly) and is faster.
+        if (GetBattlerAbility(battler) == ABILITY_TRUANT
+            && IsTruantMonVulnerable(battler, gBattlerTarget)
+            && gDisableStructs[battler].truantCounter
+            && gBattleMons[battler].hp >= gBattleMons[battler].maxHP / 2
+            && AI_SwitchMonIfSuitable(battler))
+        {
+            return TRUE;
+        }
+    }
+    return FALSE;
+}
+
 static u8 ChooseMoveOrAction_Singles(void)
 {
     u8 currentMoveArray[MAX_MON_MOVES];
@@ -434,46 +506,9 @@ static u8 ChooseMoveOrAction_Singles(void)
     if (AI_THINKING_STRUCT->aiAction & AI_ACTION_WATCH)
         return AI_CHOICE_WATCH;
 
-    // If can switch.
+    // Switch mon if there are no good moves to use.
-    if (CountUsablePartyMons(sBattler_AI) > 0
+    if (AI_ShouldSwitchIfBadMoves(sBattler_AI, FALSE))
-        && !IsAbilityPreventingEscape(sBattler_AI)
-        && !(gBattleMons[sBattler_AI].status2 & (STATUS2_WRAPPED | STATUS2_ESCAPE_PREVENTION))
-        && !(gStatuses3[sBattler_AI] & STATUS3_ROOTED)
-        && !(gBattleTypeFlags & (BATTLE_TYPE_ARENA | BATTLE_TYPE_PALACE))
-        && AI_THINKING_STRUCT->aiFlags & (AI_FLAG_CHECK_VIABILITY | AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_TRY_TO_FAINT | AI_FLAG_PREFER_BATON_PASS))
-    {
-        // Consider switching if all moves are worthless to use.
-        if (GetTotalBaseStat(gBattleMons[sBattler_AI].species) >= 310 // Mon is not weak.
-            && gBattleMons[sBattler_AI].hp >= gBattleMons[sBattler_AI].maxHP / 2)
-        {
-            s32 cap = AI_THINKING_STRUCT->aiFlags & (AI_FLAG_CHECK_VIABILITY) ? 95 : 93;
-            for (i = 0; i < MAX_MON_MOVES; i++)
-            {
-                if (AI_THINKING_STRUCT->score[i] > cap)
-                    break;
-            }
-
-            if (i == MAX_MON_MOVES && GetMostSuitableMonToSwitchInto(sBattler_AI) != PARTY_SIZE)
-            {
-                AI_THINKING_STRUCT->switchMon = TRUE;
         return AI_CHOICE_SWITCH;
-            }
-        }
-
-        // Consider switching if your mon with truant is bodied by Protect spam.
-        // Or is using a double turn semi invulnerable move(such as Fly) and is faster.
-        if (GetBattlerAbility(sBattler_AI) == ABILITY_TRUANT
-            && IsTruantMonVulnerable(sBattler_AI, gBattlerTarget)
-            && gDisableStructs[sBattler_AI].truantCounter
-            && gBattleMons[sBattler_AI].hp >= gBattleMons[sBattler_AI].maxHP / 2)
-        {
-            if (GetMostSuitableMonToSwitchInto(sBattler_AI) != PARTY_SIZE)
-            {
-                AI_THINKING_STRUCT->switchMon = TRUE;
-                return AI_CHOICE_SWITCH;
-            }
-        }
-    }
 
     numOfBestMoves = 1;
     currentMoveArray[0] = AI_THINKING_STRUCT->score[0];
@@ -588,7 +623,6 @@ static u8 ChooseMoveOrAction_Doubles(void)
                 if (i == BATTLE_PARTNER(sBattler_AI) && bestMovePointsForTarget[i] < 100)
                 {
                     bestMovePointsForTarget[i] = -1;
-                    mostViableMovesScores[0] = mostViableMovesScores[0]; // Needed to match.
                 }
             }
 
@@ -598,6 +632,10 @@ static u8 ChooseMoveOrAction_Doubles(void)
         }
     }
 
+    // Switch mon if all of the moves are bad to use against any of the target.
+    if (AI_ShouldSwitchIfBadMoves(sBattler_AI, TRUE))
+        return AI_CHOICE_SWITCH;
+
     mostMovePoints = bestMovePointsForTarget[0];
     mostViableTargetsArray[0] = 0;
     mostViableTargetsNo = 1;

src/battle_ai_switch_items.c

@@ -60,10 +60,10 @@ void GetAIPartyIndexes(u32 battler, s32 *firstId, s32 *lastId)
 
 static bool8 ShouldSwitchIfAllBadMoves(u32 battler)
 {
-    if (gBattleResources->ai->switchMon)
+    if (AI_DATA->shouldSwitchMon & gBitTable[battler])
     {
-        gBattleResources->ai->switchMon = 0;
+        AI_DATA->shouldSwitchMon &= ~(gBitTable[battler]);
-        *(gBattleStruct->AI_monToSwitchIntoId + battler) = PARTY_SIZE;
+        gBattleStruct->AI_monToSwitchIntoId[battler] = AI_DATA->monToSwitchId[battler];
         BtlController_EmitTwoReturnValues(battler, BUFFER_B, B_ACTION_SWITCH, 0);
         return TRUE;
     }

src/battle_anim.c

@@ -275,6 +275,7 @@ void LaunchBattleAnimation(u32 animType, u32 animId)
         case B_ANIM_WISH_HEAL:
         case B_ANIM_MEGA_EVOLUTION:
         case B_ANIM_PRIMAL_REVERSION:
+        case B_ANIM_ULTRA_BURST:
         case B_ANIM_GULP_MISSILE:
             sAnimHideHpBoxes = TRUE;
             break;

src/battle_anim_new.c

@@ -4761,6 +4761,18 @@ const struct SpriteTemplate gSpriteTemplate_BitterMaliceRing = {
     .callback = AnimParticleInVortex 
 };
 
+//ultra burst
+const struct SpriteTemplate gUltraBurstSymbolSpriteTemplate =
+{
+    .tileTag = ANIM_TAG_ULTRA_BURST_SYMBOL,
+    .paletteTag = ANIM_TAG_ULTRA_BURST_SYMBOL,
+    .oam = &gOamData_AffineDouble_ObjBlend_32x32,
+    .anims = gDummySpriteAnimTable,
+    .images = NULL,
+    .affineAnims = gAffineAnims_LusterPurgeCircle,
+    .callback = AnimSpriteOnMonPos
+};
+
 // Z MOVES
 //activate
 const struct SpriteTemplate gZMoveSymbolSpriteTemplate =

src/battle_controller_opponent.c

@@ -561,6 +561,8 @@ static void OpponentHandleChooseMove(u32 battler)
                         QueueZMove(battler, chosenMove);
                     if (CanMegaEvolve(battler)) // If opponent can mega evolve, do it.
                         BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, (chosenMoveId) | (RET_MEGA_EVOLUTION) | (gBattlerTarget << 8));
+                    else if (CanUltraBurst(battler))
+                        BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, (chosenMoveId) | (RET_ULTRA_BURST) | (gBattlerTarget << 8));
                     else
                         BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, (chosenMoveId) | (gBattlerTarget << 8));
                 }

src/battle_controller_player.c

@@ -436,6 +436,8 @@ static void HandleInputChooseTarget(u32 battler)
         gSprites[gBattlerSpriteIds[gMultiUsePlayerCursor]].callback = SpriteCB_HideAsMoveTarget;
         if (gBattleStruct->mega.playerSelect)
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_MEGA_EVOLUTION | (gMultiUsePlayerCursor << 8));
+        else if (gBattleStruct->burst.playerSelect)
+            BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_ULTRA_BURST | (gMultiUsePlayerCursor << 8));
         else
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | (gMultiUsePlayerCursor << 8));
         EndBounceEffect(gMultiUsePlayerCursor, BOUNCE_HEALTHBOX);
@@ -594,9 +596,11 @@ static void HandleInputShowEntireFieldTargets(u32 battler)
         HideAllTargets();
         if (gBattleStruct->mega.playerSelect)
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_MEGA_EVOLUTION | (gMultiUsePlayerCursor << 8));
+        else if (gBattleStruct->burst.playerSelect)
+            BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_ULTRA_BURST | (gMultiUsePlayerCursor << 8));
         else
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | (gMultiUsePlayerCursor << 8));
-        HideMegaTriggerSprite();
+        HideTriggerSprites();
         PlayerBufferExecCompleted(battler);
     }
     else if (JOY_NEW(B_BUTTON) || gPlayerDpadHoldFrames > 59)
@@ -622,6 +626,8 @@ static void HandleInputShowTargets(u32 battler)
         HideShownTargets(battler);
         if (gBattleStruct->mega.playerSelect)
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_MEGA_EVOLUTION | (gMultiUsePlayerCursor << 8));
+        else if (gBattleStruct->burst.playerSelect)
+            BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_ULTRA_BURST | (gMultiUsePlayerCursor << 8));
         else
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | (gMultiUsePlayerCursor << 8));
         HideTriggerSprites();
@@ -737,6 +743,8 @@ static void HandleInputChooseMove(u32 battler)
         default:
             if (gBattleStruct->mega.playerSelect)
                 BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_MEGA_EVOLUTION | (gMultiUsePlayerCursor << 8));
+            else if (gBattleStruct->burst.playerSelect)
+                BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | RET_ULTRA_BURST | (gMultiUsePlayerCursor << 8));
             else
                 BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, gMoveSelectionCursor[battler] | (gMultiUsePlayerCursor << 8));
             HideTriggerSprites();
@@ -773,6 +781,7 @@ static void HandleInputChooseMove(u32 battler)
         else
         {
             gBattleStruct->mega.playerSelect = FALSE;
+            gBattleStruct->burst.playerSelect = FALSE;
             gBattleStruct->zmove.viable = FALSE;
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, 0xFFFF);
             HideTriggerSprites();
@@ -857,6 +866,12 @@ static void HandleInputChooseMove(u32 battler)
             ChangeMegaTriggerSprite(gBattleStruct->mega.triggerSpriteId, gBattleStruct->mega.playerSelect);
             PlaySE(SE_SELECT);
         }
+        else if (CanUltraBurst(battler))
+        {
+            gBattleStruct->burst.playerSelect ^= 1;
+            ChangeBurstTriggerSprite(gBattleStruct->burst.triggerSpriteId, gBattleStruct->burst.playerSelect);
+            PlaySE(SE_SELECT);
+        }
         else if (gBattleStruct->zmove.viable)
         {
             // show z move name / info
@@ -873,6 +888,7 @@ static void HandleInputChooseMove(u32 battler)
 static void ReloadMoveNames(u32 battler)
 {
     gBattleStruct->mega.playerSelect = FALSE;
+    gBattleStruct->burst.playerSelect = FALSE;
     gBattleStruct->zmove.viewing = FALSE;
     MoveSelectionDestroyCursorAt(battler);
     MoveSelectionDisplayMoveNames(battler);
@@ -1946,10 +1962,15 @@ static void PlayerHandleChooseMove(u32 battler)
 
         InitMoveSelectionsVarsAndStrings(battler);
         gBattleStruct->mega.playerSelect = FALSE;
+        gBattleStruct->burst.playerSelect = FALSE;
         if (!IsMegaTriggerSpriteActive())
             gBattleStruct->mega.triggerSpriteId = 0xFF;
         if (CanMegaEvolve(battler))
             CreateMegaTriggerSprite(battler, 0);
+        if (!IsBurstTriggerSpriteActive())
+            gBattleStruct->burst.triggerSpriteId = 0xFF;
+        if (CanUltraBurst(battler))
+            CreateBurstTriggerSprite(battler, 0);
         if (!IsZMoveTriggerSpriteActive())
             gBattleStruct->zmove.triggerSpriteId = 0xFF;
 

src/battle_controller_player_partner.c

@@ -352,6 +352,12 @@ static void PlayerPartnerHandleChooseMove(u32 battler)
     chosenMoveId = gBattleStruct->aiMoveOrAction[battler];
     gBattlerTarget = gBattleStruct->aiChosenTarget[battler];
 
+    if (chosenMoveId == AI_CHOICE_SWITCH)
+    {
+        BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, 0xFFFF);
+    }
+    else
+    {
         if (gBattleMoves[moveInfo->moves[chosenMoveId]].target & (MOVE_TARGET_USER | MOVE_TARGET_USER_OR_SELECTED))
             gBattlerTarget = battler;
         if (gBattleMoves[moveInfo->moves[chosenMoveId]].target & MOVE_TARGET_BOTH)
@@ -367,8 +373,11 @@ static void PlayerPartnerHandleChooseMove(u32 battler)
         // If partner can mega evolve, do it.
         if (CanMegaEvolve(battler))
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, (chosenMoveId) | (RET_MEGA_EVOLUTION) | (gBattlerTarget << 8));
+        else if (CanUltraBurst(battler))
+            BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, (chosenMoveId) | (RET_ULTRA_BURST) | (gBattlerTarget << 8));
         else
             BtlController_EmitTwoReturnValues(battler, BUFFER_B, 10, (chosenMoveId) | (gBattlerTarget << 8));
+    }
 
     PlayerPartnerBufferExecCompleted(battler);
 }
@@ -382,7 +391,7 @@ static void PlayerPartnerHandleChoosePokemon(u32 battler)
         chosenMonId = gSelectedMonPartyId = GetFirstFaintedPartyIndex(battler);
     }
     // Switching out
-    else
+    else if (gBattleStruct->monToSwitchIntoId[battler] == PARTY_SIZE)
     {
         chosenMonId = GetMostSuitableMonToSwitchInto(battler);
         if (chosenMonId == PARTY_SIZE) // just switch to the next mon
@@ -402,6 +411,12 @@ static void PlayerPartnerHandleChoosePokemon(u32 battler)
         }
         *(gBattleStruct->monToSwitchIntoId + battler) = chosenMonId;
     }
+    else // Mon to switch out has been already chosen.
+    {
+        chosenMonId = gBattleStruct->monToSwitchIntoId[battler];
+        gBattleStruct->AI_monToSwitchIntoId[battler] = PARTY_SIZE;
+        gBattleStruct->monToSwitchIntoId[battler] = chosenMonId;
+    }
     BtlController_EmitChosenMonReturnValue(battler, BUFFER_B, chosenMonId, NULL);
     PlayerPartnerBufferExecCompleted(battler);
 }

src/battle_interface.c

@@ -194,6 +194,7 @@ static void SpriteCB_StatusSummaryBalls_Exit(struct Sprite *);
 static void SpriteCB_StatusSummaryBalls_OnSwitchout(struct Sprite *);
 
 static void SpriteCb_MegaTrigger(struct Sprite *);
+static void SpriteCb_BurstTrigger(struct Sprite *);
 static void MegaIndicator_SetVisibilities(u32 healthboxId, bool32 invisible);
 static void MegaIndicator_UpdateLevel(u32 healthboxId, u32 level);
 static void MegaIndicator_CreateSprite(u32 battlerId, u32 healthboxSpriteId);
@@ -676,6 +677,64 @@ static const struct SpriteTemplate sSpriteTemplate_MegaTrigger =
     .callback = SpriteCb_MegaTrigger
 };
 
+static const u8 ALIGNED(4) sBurstTriggerGfx[] = INCBIN_U8("graphics/battle_interface/burst_trigger.4bpp");
+static const u16 sBurstTriggerPal[] = INCBIN_U16("graphics/battle_interface/burst_trigger.gbapal");
+
+static const struct SpriteSheet sSpriteSheet_BurstTrigger =
+{
+    sBurstTriggerGfx, sizeof(sBurstTriggerGfx), TAG_BURST_TRIGGER_TILE
+};
+static const struct SpritePalette sSpritePalette_BurstTrigger =
+{
+    sBurstTriggerPal, TAG_BURST_TRIGGER_PAL
+};
+
+static const struct OamData sOamData_BurstTrigger =
+{
+    .y = 0,
+    .affineMode = 0,
+    .objMode = 0,
+    .mosaic = 0,
+    .bpp = 0,
+    .shape = ST_OAM_SQUARE,
+    .x = 0,
+    .matrixNum = 0,
+    .size = 2,
+    .tileNum = 0,
+    .priority = 1,
+    .paletteNum = 0,
+    .affineParam = 0,
+};
+
+static const union AnimCmd sSpriteAnim_BurstTriggerOff[] =
+{
+    ANIMCMD_FRAME(0, 0),
+    ANIMCMD_END
+};
+
+static const union AnimCmd sSpriteAnim_BurstTriggerOn[] =
+{
+    ANIMCMD_FRAME(16, 0),
+    ANIMCMD_END
+};
+
+static const union AnimCmd *const sSpriteAnimTable_BurstTrigger[] =
+{
+    sSpriteAnim_BurstTriggerOff,
+    sSpriteAnim_BurstTriggerOn,
+};
+
+static const struct SpriteTemplate sSpriteTemplate_BurstTrigger =
+{
+    .tileTag = TAG_BURST_TRIGGER_TILE,
+    .paletteTag = TAG_BURST_TRIGGER_PAL,
+    .oam = &sOamData_BurstTrigger,
+    .anims = sSpriteAnimTable_BurstTrigger,
+    .images = NULL,
+    .affineAnims = gDummySpriteAffineAnimTable,
+    .callback = SpriteCb_BurstTrigger
+};
+
 // Because the healthbox is too large to fit into one sprite, it is divided into two sprites.
 // healthboxLeft  or healthboxMain  is the left part that is used as the 'main' sprite.
 // healthboxRight or healthboxOther is the right part of the healthbox.
@@ -1418,6 +1477,7 @@ void HideMegaTriggerSprite(void)
 void HideTriggerSprites(void)
 {
     HideMegaTriggerSprite();
+    HideBurstTriggerSprite();
     HideZMoveTriggerSprite();
 }
 
@@ -1433,6 +1493,128 @@ void DestroyMegaTriggerSprite(void)
 #undef tBattler
 #undef tHide
 
+// Ultra Burst Trigger icon functions.
+void ChangeBurstTriggerSprite(u8 spriteId, u8 animId)
+{
+    StartSpriteAnim(&gSprites[spriteId], animId);
+}
+
+#define SINGLES_BURST_TRIGGER_POS_X_OPTIMAL (30)
+#define SINGLES_BURST_TRIGGER_POS_X_PRIORITY (31)
+#define SINGLES_BURST_TRIGGER_POS_X_SLIDE (15)
+#define SINGLES_BURST_TRIGGER_POS_Y_DIFF (-11)
+
+#define DOUBLES_BURST_TRIGGER_POS_X_OPTIMAL (30)
+#define DOUBLES_BURST_TRIGGER_POS_X_PRIORITY (31)
+#define DOUBLES_BURST_TRIGGER_POS_X_SLIDE (15)
+#define DOUBLES_BURST_TRIGGER_POS_Y_DIFF (-4)
+
+#define tBattler    data[0]
+#define tHide       data[1]
+
+void CreateBurstTriggerSprite(u8 battlerId, u8 palId)
+{
+    LoadSpritePalette(&sSpritePalette_BurstTrigger);
+    if (GetSpriteTileStartByTag(TAG_BURST_TRIGGER_TILE) == 0xFFFF)
+        LoadSpriteSheet(&sSpriteSheet_BurstTrigger);
+    if (gBattleStruct->burst.triggerSpriteId == 0xFF)
+    {
+        if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE)
+            gBattleStruct->burst.triggerSpriteId = CreateSprite(&sSpriteTemplate_BurstTrigger,
+                                                             gSprites[gHealthboxSpriteIds[battlerId]].x - DOUBLES_BURST_TRIGGER_POS_X_SLIDE,
+                                                             gSprites[gHealthboxSpriteIds[battlerId]].y - DOUBLES_BURST_TRIGGER_POS_Y_DIFF, 0);
+        else
+            gBattleStruct->burst.triggerSpriteId = CreateSprite(&sSpriteTemplate_BurstTrigger,
+                                                             gSprites[gHealthboxSpriteIds[battlerId]].x - SINGLES_BURST_TRIGGER_POS_X_SLIDE,
+                                                             gSprites[gHealthboxSpriteIds[battlerId]].y - SINGLES_BURST_TRIGGER_POS_Y_DIFF, 0);
+    }
+    gSprites[gBattleStruct->burst.triggerSpriteId].tBattler = battlerId;
+    gSprites[gBattleStruct->burst.triggerSpriteId].tHide = FALSE;
+
+    ChangeBurstTriggerSprite(gBattleStruct->burst.triggerSpriteId, palId);
+}
+
+static void SpriteCb_BurstTrigger(struct Sprite *sprite)
+{
+    s32 xSlide, xPriority, xOptimal;
+    s32 yDiff;
+
+    if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE)
+    {
+        xSlide = DOUBLES_BURST_TRIGGER_POS_X_SLIDE;
+        xPriority = DOUBLES_BURST_TRIGGER_POS_X_PRIORITY;
+        xOptimal = DOUBLES_BURST_TRIGGER_POS_X_OPTIMAL;
+        yDiff = DOUBLES_BURST_TRIGGER_POS_Y_DIFF;
+    }
+    else
+    {
+        xSlide = SINGLES_BURST_TRIGGER_POS_X_SLIDE;
+        xPriority = SINGLES_BURST_TRIGGER_POS_X_PRIORITY;
+        xOptimal = SINGLES_BURST_TRIGGER_POS_X_OPTIMAL;
+        yDiff = SINGLES_BURST_TRIGGER_POS_Y_DIFF;
+    }
+
+    if (sprite->tHide)
+    {
+        if (sprite->x != gSprites[gHealthboxSpriteIds[sprite->tBattler]].x - xSlide)
+            sprite->x++;
+
+        if (sprite->x >= gSprites[gHealthboxSpriteIds[sprite->tBattler]].x - xPriority)
+            sprite->oam.priority = 2;
+        else
+            sprite->oam.priority = 1;
+
+        sprite->y = gSprites[gHealthboxSpriteIds[sprite->tBattler]].y - yDiff;
+        sprite->y2 = gSprites[gHealthboxSpriteIds[sprite->tBattler]].y2 - yDiff;
+        if (sprite->x == gSprites[gHealthboxSpriteIds[sprite->tBattler]].x - xSlide)
+            DestroyBurstTriggerSprite();
+    }
+    else
+    {
+        if (sprite->x != gSprites[gHealthboxSpriteIds[sprite->tBattler]].x - xOptimal)
+            sprite->x--;
+
+        if (sprite->x >= gSprites[gHealthboxSpriteIds[sprite->tBattler]].x - xPriority)
+            sprite->oam.priority = 2;
+        else
+            sprite->oam.priority = 1;
+
+        sprite->y = gSprites[gHealthboxSpriteIds[sprite->tBattler]].y - yDiff;
+        sprite->y2 = gSprites[gHealthboxSpriteIds[sprite->tBattler]].y2 - yDiff;
+    }
+}
+
+bool32 IsBurstTriggerSpriteActive(void)
+{
+    if (GetSpriteTileStartByTag(TAG_BURST_TRIGGER_TILE) == 0xFFFF)
+        return FALSE;
+    else if (IndexOfSpritePaletteTag(TAG_BURST_TRIGGER_PAL) != 0xFF)
+        return TRUE;
+    else
+        return FALSE;
+}
+
+void HideBurstTriggerSprite(void)
+{
+    if (gBattleStruct->burst.triggerSpriteId >= MAX_SPRITES)
+        return;
+    ChangeBurstTriggerSprite(gBattleStruct->burst.triggerSpriteId, 0);
+    gSprites[gBattleStruct->burst.triggerSpriteId].tHide = TRUE;
+}
+
+void DestroyBurstTriggerSprite(void)
+{
+    FreeSpritePaletteByTag(TAG_BURST_TRIGGER_PAL);
+    FreeSpriteTilesByTag(TAG_BURST_TRIGGER_TILE);
+    if (gBattleStruct->burst.triggerSpriteId != 0xFF)
+        DestroySprite(&gSprites[gBattleStruct->burst.triggerSpriteId]);
+    gBattleStruct->burst.triggerSpriteId = 0xFF;
+}
+
+#undef tBattler
+#undef tHide
+
+
 // Code for Mega Evolution (And Alpha/Omega) Trigger icon visible on the battler's healthbox.
 enum
 {

src/battle_main.c

@@ -3111,6 +3111,7 @@ static void BattleStartClearSetData(void)
     gBattleStruct->arenaLostOpponentMons = 0;
 
     gBattleStruct->mega.triggerSpriteId = 0xFF;
+    gBattleStruct->burst.triggerSpriteId = 0xFF;
 
     for (i = 0; i < ARRAY_COUNT(gSideTimers); i++)
     {
@@ -4288,6 +4289,7 @@ static void HandleTurnActionSelectionState(void)
                     }
 
                     gBattleStruct->mega.toEvolve &= ~(gBitTable[BATTLE_PARTNER(GetBattlerPosition(battler))]);
+                    gBattleStruct->burst.toBurst &= ~(gBitTable[BATTLE_PARTNER(GetBattlerPosition(battler))]);
                     gBattleStruct->zmove.toBeUsed[BATTLE_PARTNER(GetBattlerPosition(battler))] = MOVE_NONE;
                     BtlController_EmitEndBounceEffect(battler, BUFFER_A);
                     MarkBattlerForControllerExec(battler);
@@ -4374,11 +4376,14 @@ static void HandleTurnActionSelectionState(void)
                                 RecordedBattle_SetBattlerAction(battler, gBattleResources->bufferB[battler][2]);
                                 RecordedBattle_SetBattlerAction(battler, gBattleResources->bufferB[battler][3]);
                             }
-                            *(gBattleStruct->chosenMovePositions + battler) = gBattleResources->bufferB[battler][2] & ~RET_MEGA_EVOLUTION;
+
-                            gChosenMoveByBattler[battler] = gBattleMons[battler].moves[*(gBattleStruct->chosenMovePositions + battler)];
+                            gBattleStruct->chosenMovePositions[battler] = gBattleResources->bufferB[battler][2] & ~(RET_MEGA_EVOLUTION | RET_ULTRA_BURST);
-                            *(gBattleStruct->moveTarget + battler) = gBattleResources->bufferB[battler][3];
+                            gChosenMoveByBattler[battler] = gBattleMons[battler].moves[gBattleStruct->chosenMovePositions[battler]];
+                            gBattleStruct->moveTarget[battler] = gBattleResources->bufferB[battler][3];
                             if (gBattleResources->bufferB[battler][2] & RET_MEGA_EVOLUTION)
                                 gBattleStruct->mega.toEvolve |= gBitTable[battler];
+                            else if (gBattleResources->bufferB[battler][2] & RET_ULTRA_BURST)
+                                gBattleStruct->burst.toBurst |= gBitTable[battler];
                             gBattleCommunication[battler]++;
                         }
                         break;
@@ -4996,9 +5001,9 @@ static void PopulateArrayWithBattlers(u8 *battlers)
 
 static bool32 TryDoMegaEvosBeforeMoves(void)
 {
-    if (!(gHitMarker & HITMARKER_RUN) && gBattleStruct->mega.toEvolve)
+    if (!(gHitMarker & HITMARKER_RUN) && (gBattleStruct->mega.toEvolve || gBattleStruct->burst.toBurst))
     {
-        u32 i;
+        u32 i, battler;
         struct Pokemon *party;
         struct Pokemon *mon;
         u8 megaOrder[MAX_BATTLERS_COUNT];
@@ -5021,6 +5026,18 @@ static bool32 TryDoMegaEvosBeforeMoves(void)
                     BattleScriptExecute(BattleScript_MegaEvolution);
                 return TRUE;
             }
+
+            if (gBattleStruct->burst.toBurst & gBitTable[megaOrder[i]]
+                && !(gProtectStructs[megaOrder[i]].noValidMoves))
+            {
+                battler = gBattlerAttacker = megaOrder[i];
+                gBattleStruct->burst.toBurst &= ~(gBitTable[battler]);
+                gLastUsedItem = gBattleMons[battler].item;
+                party = GetBattlerParty(battler);
+                mon = &party[gBattlerPartyIndexes[battler]];
+                BattleScriptExecute(BattleScript_UltraBurst);
+                return TRUE;
+            }
         }
     }
 

src/battle_message.c

@@ -800,6 +800,9 @@ static const u8 sText_ItemRestoredSpeciesPP[] = _("{B_BUFF1} had its\nPP restore
 static const u8 sText_AtkTrappedDef[] = _("{B_ATK_NAME_WITH_PREFIX} trapped\nthe {B_DEF_NAME_WITH_PREFIX}!");
 static const u8 sText_MirrorHerbCopied[] = _("{B_SCR_ACTIVE_NAME_WITH_PREFIX} used its {B_LAST_ITEM}\nto mirror its opponent's stat changes!");
 static const u8 sText_PkmnItemMelted[] = _("{B_ATK_NAME_WITH_PREFIX} corroded\n{B_DEF_NAME_WITH_PREFIX}'s {B_LAST_ITEM}!");
+static const u8 sText_UltraBurstReacting[] = _("Bright light is about to\nburst out of {B_ATK_NAME_WITH_PREFIX}!");
+static const u8 sText_UltraBurstCompleted[] = _("{B_ATK_NAME_WITH_PREFIX} regained its\ntrue power through Ultra Burst!");
+
 
 const u8 *const gBattleStringsTable[BATTLESTRINGS_COUNT] =
 {
@@ -1456,6 +1459,8 @@ const u8 *const gBattleStringsTable[BATTLESTRINGS_COUNT] =
     [STRINGID_PKMNFROSTBITEHEALED - BATTLESTRINGS_TABLE_START] = sText_PkmnFrostbiteHealed,
     [STRINGID_PKMNFROSTBITEHEALED2 - BATTLESTRINGS_TABLE_START] = sText_PkmnFrostbiteHealed2,
     [STRINGID_PKMNFROSTBITEHEALEDBY - BATTLESTRINGS_TABLE_START] = sText_PkmnFrostbiteHealedBy,
+    [STRINGID_ULTRABURSTREACTING - BATTLESTRINGS_TABLE_START] = sText_UltraBurstReacting,
+    [STRINGID_ULTRABURSTCOMPLETED - BATTLESTRINGS_TABLE_START] = sText_UltraBurstCompleted,
 };
 
 const u16 gTrainerUsedItemStringIds[] =

src/battle_script_commands.c

@@ -4964,7 +4964,8 @@ static void PlayAnimation(u32 battler, u8 animId, const u16 *argPtr, const u8 *n
      || animId == B_ANIM_ILLUSION_OFF
      || animId == B_ANIM_FORM_CHANGE
      || animId == B_ANIM_SUBSTITUTE_FADE
-     || animId == B_ANIM_PRIMAL_REVERSION)
+     || animId == B_ANIM_PRIMAL_REVERSION
+     || animId == B_ANIM_ULTRA_BURST)
     {
         BtlController_EmitBattleAnimation(battler, BUFFER_A, animId, *argPtr);
         MarkBattlerForControllerExec(battler);
@@ -8455,7 +8456,7 @@ static bool32 CourtChangeSwapSideStatuses(void)
     SWAP(sideTimerPlayer->stickyWebBattlerSide, sideTimerOpp->stickyWebBattlerSide, temp);
 }
 
-static void HandleScriptMegaPrimal(u32 caseId, u32 battler, bool32 isMega)
+static void HandleScriptMegaPrimalBurst(u32 caseId, u32 battler, u32 type)
 {
     struct Pokemon *party = GetBattlerParty(battler);
     struct Pokemon *mon = &party[gBattlerPartyIndexes[battler]];
@@ -8465,13 +8466,15 @@ static void HandleScriptMegaPrimal(u32 caseId, u32 battler, bool32 isMega)
     // Change species.
     if (caseId == 0)
     {
-        if (isMega)
+        if (type == HANDLE_TYPE_MEGA_EVOLUTION)
         {
             if (!TryBattleFormChange(battler, FORM_CHANGE_BATTLE_MEGA_EVOLUTION_ITEM))
                 TryBattleFormChange(battler, FORM_CHANGE_BATTLE_MEGA_EVOLUTION_MOVE);
         }
-        else
+        else if (type == HANDLE_TYPE_PRIMAL_REVERSION)
             TryBattleFormChange(battler, FORM_CHANGE_BATTLE_PRIMAL_REVERSION);
+        else
+            TryBattleFormChange(battler, FORM_CHANGE_BATTLE_ULTRA_BURST);
 
         PREPARE_SPECIES_BUFFER(gBattleTextBuff1, gBattleMons[battler].species);
 
@@ -8484,8 +8487,10 @@ static void HandleScriptMegaPrimal(u32 caseId, u32 battler, bool32 isMega)
         UpdateHealthboxAttribute(gHealthboxSpriteIds[battler], mon, HEALTHBOX_ALL);
         if (side == B_SIDE_OPPONENT)
             SetBattlerShadowSpriteCallback(battler, gBattleMons[battler].species);
-        if (isMega)
+        if (type == HANDLE_TYPE_MEGA_EVOLUTION)
             gBattleStruct->mega.alreadyEvolved[position] = TRUE;
+        if (type == HANDLE_TYPE_ULTRA_BURST)
+            gBattleStruct->burst.alreadyBursted[position] = TRUE;
     }
 }
 
@@ -9515,14 +9520,21 @@ static void Cmd_various(void)
     case VARIOUS_HANDLE_MEGA_EVO:
     {
         VARIOUS_ARGS(u8 case_);
-        HandleScriptMegaPrimal(cmd->case_, battler, TRUE);
+        HandleScriptMegaPrimalBurst(cmd->case_, battler, HANDLE_TYPE_MEGA_EVOLUTION);
         gBattlescriptCurrInstr = cmd->nextInstr;
         return;
     }
     case VARIOUS_HANDLE_PRIMAL_REVERSION:
     {
         VARIOUS_ARGS(u8 case_);
-        HandleScriptMegaPrimal(cmd->case_, battler, FALSE);
+        HandleScriptMegaPrimalBurst(cmd->case_, battler, HANDLE_TYPE_PRIMAL_REVERSION);
+        gBattlescriptCurrInstr = cmd->nextInstr;
+        return;
+    }
+    case VARIOUS_HANDLE_ULTRA_BURST:
+    {
+        VARIOUS_ARGS(u8 case_);
+        HandleScriptMegaPrimalBurst(cmd->case_, battler, HANDLE_TYPE_ULTRA_BURST);
         gBattlescriptCurrInstr = cmd->nextInstr;
         return;
     }

src/battle_util.c

@@ -1608,7 +1608,7 @@ static bool32 IsBelchPreventingMove(u32 battler, u32 move)
 u32 TrySetCantSelectMoveBattleScript(u32 battler)
 {
     u32 limitations = 0;
-    u8 moveId = gBattleResources->bufferB[battler][2] & ~RET_MEGA_EVOLUTION;
+    u8 moveId = gBattleResources->bufferB[battler][2] & ~(RET_MEGA_EVOLUTION | RET_ULTRA_BURST);
     u32 move = gBattleMons[battler].moves[moveId];
     u32 holdEffect = GetBattlerHoldEffect(battler, TRUE);
     u16 *choicedMove = &gBattleStruct->choicedMove[battler];
@@ -10083,6 +10083,7 @@ bool32 DoesSpeciesUseHoldItemToChangeForm(u16 species, u16 heldItemId)
             {
             case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_ITEM:
             case FORM_CHANGE_BATTLE_PRIMAL_REVERSION:
+            case FORM_CHANGE_BATTLE_ULTRA_BURST:
             case FORM_CHANGE_ITEM_HOLD:
                 if (formChanges[i].param1 == heldItemId)
                     return TRUE;
@@ -10157,6 +10158,61 @@ bool32 CanMegaEvolve(u8 battler)
     return FALSE;
 }
 
+bool32 CanUltraBurst(u8 battler)
+{
+    u32 itemId, holdEffect, species;
+    struct Pokemon *mon;
+    u8 battlerPosition = GetBattlerPosition(battler);
+    u8 partnerPosition = GetBattlerPosition(BATTLE_PARTNER(battler));
+
+    // Check if Player has a Z Ring
+    if ((GetBattlerPosition(battler) == B_POSITION_PLAYER_LEFT || (!(gBattleTypeFlags & BATTLE_TYPE_MULTI) && GetBattlerPosition(battler) == B_POSITION_PLAYER_RIGHT))
+     && !CheckBagHasItem(ITEM_Z_POWER_RING, 1))
+        return FALSE;
+
+    // Check if trainer already ultra bursted a pokemon.
+    if (gBattleStruct->burst.alreadyBursted[battlerPosition])
+        return FALSE;
+
+    // Cannot use z move and ultra burst on same turn
+    if (gBattleStruct->zmove.toBeUsed[battler])
+        return FALSE;
+
+    if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE
+     && IsPartnerMonFromSameTrainer(battler)
+     && (gBattleStruct->burst.alreadyBursted[partnerPosition] || (gBattleStruct->burst.toBurst & gBitTable[BATTLE_PARTNER(battler)])))
+        return FALSE;
+
+    // Check if mon is currently held by Sky Drop
+    if (gStatuses3[battler] & STATUS3_SKY_DROPPED)
+        return FALSE;
+
+    // Gets mon data.
+    if (GetBattlerSide(battler) == B_SIDE_OPPONENT)
+        mon = &gEnemyParty[gBattlerPartyIndexes[battler]];
+    else
+        mon = &gPlayerParty[gBattlerPartyIndexes[battler]];
+
+    species = GetMonData(mon, MON_DATA_SPECIES);
+    itemId = GetMonData(mon, MON_DATA_HELD_ITEM);
+
+    // Check if there is an entry in the evolution table for Ultra Burst.
+    if (GetBattleFormChangeTargetSpecies(battler, FORM_CHANGE_BATTLE_ULTRA_BURST) != SPECIES_NONE)
+    {
+        if (itemId == ITEM_ENIGMA_BERRY_E_READER)
+            holdEffect = gEnigmaBerries[battler].holdEffect;
+        else
+            holdEffect = ItemId_GetHoldEffect(itemId);
+
+        // Can Ultra Burst via Z Crystal.
+        if (holdEffect == HOLD_EFFECT_Z_CRYSTAL)
+            return TRUE;
+    }
+
+    // No checks passed, the mon CAN'T ultra burst.
+    return FALSE;
+}
+
 bool32 IsBattlerMegaEvolved(u8 battler)
 {
     // While Transform does copy stats and visuals, it shouldn't be counted as true Mega Evolution.
@@ -10173,6 +10229,14 @@ bool32 IsBattlerPrimalReverted(u8 battler)
     return (gSpeciesInfo[gBattleMons[battler].species].flags & SPECIES_FLAG_PRIMAL_REVERSION);
 }
 
+bool32 IsBattlerUltraBursted(u8 battler)
+{
+    // While Transform does copy stats and visuals, it shouldn't be counted as true Ultra Burst.
+    if (gBattleMons[battler].status2 & STATUS2_TRANSFORMED)
+        return FALSE;
+    return (gSpeciesInfo[gBattleMons[battler].species].flags & SPECIES_FLAG_ULTRA_BURST);
+}
+
 // Returns SPECIES_NONE if no form change is possible
 u16 GetBattleFormChangeTargetSpecies(u8 battler, u16 method)
 {
@@ -10196,6 +10260,7 @@ u16 GetBattleFormChangeTargetSpecies(u8 battler, u16 method)
                 {
                 case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_ITEM:
                 case FORM_CHANGE_BATTLE_PRIMAL_REVERSION:
+                case FORM_CHANGE_BATTLE_ULTRA_BURST:
                     if (heldItem == formChanges[i].param1)
                         targetSpecies = formChanges[i].targetSpecies;
                     break;
@@ -10266,8 +10331,8 @@ bool32 CanBattlerFormChange(u8 battler, u16 method)
     if (gBattleMons[battler].status2 & STATUS2_TRANSFORMED
         && B_TRANSFORM_FORM_CHANGES >= GEN_5)
         return FALSE;
-    // Mega Evolved Pokémon should always revert to normal upon fainting or ending the battle.
+    // Mega Evolved and Ultra Bursted Pokémon should always revert to normal upon fainting or ending the battle.
-    if (IsBattlerMegaEvolved(battler) && (method == FORM_CHANGE_FAINT || method == FORM_CHANGE_END_BATTLE))
+    if ((IsBattlerMegaEvolved(battler) || IsBattlerUltraBursted(battler)) && (method == FORM_CHANGE_FAINT || method == FORM_CHANGE_END_BATTLE))
         return TRUE;
     else if (IsBattlerPrimalReverted(battler) && (method == FORM_CHANGE_END_BATTLE))
         return TRUE;
@@ -10303,8 +10368,8 @@ bool32 TryBattleFormChange(u8 battler, u16 method)
     {
         bool8 restoreSpecies = FALSE;
 
-        // Mega Evolved Pokémon should always revert to normal upon fainting or ending the battle, so no need to add it to the form change tables.
+        // Mega Evolved and Ultra Bursted Pokémon should always revert to normal upon fainting or ending the battle, so no need to add it to the form change tables.
-        if (IsBattlerMegaEvolved(battler) && (method == FORM_CHANGE_FAINT || method == FORM_CHANGE_END_BATTLE))
+        if ((IsBattlerMegaEvolved(battler) || IsBattlerUltraBursted(battler)) && (method == FORM_CHANGE_FAINT || method == FORM_CHANGE_END_BATTLE))
             restoreSpecies = TRUE;
 
         // Unlike Megas, Primal Reversion isn't canceled on fainting.

src/data/pokemon/form_change_table_pointers.h

@@ -210,6 +210,8 @@ const struct FormChange *const gFormChangeTablePointers[NUM_SPECIES] =
     [SPECIES_MINIOR_CORE_VIOLET] = sMiniorVioletFormChangeTable,
     [SPECIES_MINIOR_METEOR_YELLOW] = sMiniorYellowFormChangeTable,
     [SPECIES_MINIOR_CORE_YELLOW] = sMiniorYellowFormChangeTable,
+    [SPECIES_NECROZMA_DUSK_MANE] = sNecrozmaDuskManeFormChangeTable,
+    [SPECIES_NECROZMA_DAWN_WINGS] = sNecrozmaDawnWingsFormChangeTable,
 #endif
 #if P_GEN_8_POKEMON == TRUE
     [SPECIES_CRAMORANT] = sCramorantFormChangeTable,

src/data/pokemon/form_change_tables.h

@@ -548,6 +548,14 @@ static const struct FormChange sMiniorYellowFormChangeTable[] = {
     {FORM_CHANGE_END_BATTLE,        SPECIES_MINIOR_CORE_YELLOW},
     {FORM_CHANGE_TERMINATOR},
 };
+static const struct FormChange sNecrozmaDuskManeFormChangeTable[] = {
+    {FORM_CHANGE_BATTLE_ULTRA_BURST,    SPECIES_NECROZMA_ULTRA, ITEM_ULTRANECROZIUM_Z},
+    {FORM_CHANGE_TERMINATOR},
+};
+static const struct FormChange sNecrozmaDawnWingsFormChangeTable[] = {
+    {FORM_CHANGE_BATTLE_ULTRA_BURST,    SPECIES_NECROZMA_ULTRA, ITEM_ULTRANECROZIUM_Z},
+    {FORM_CHANGE_TERMINATOR},
+};
 #endif
 
 #if P_GEN_8_POKEMON == TRUE

src/data/pokemon/species_info.h

@@ -24484,7 +24484,7 @@ const struct SpeciesInfo gSpeciesInfo[] =
         .abilities = {ABILITY_NEUROFORCE, ABILITY_NONE},
         .bodyColor = BODY_COLOR_YELLOW,
         .noFlip = TRUE,
-        .flags = SPECIES_FLAG_LEGENDARY,
+        .flags = SPECIES_FLAG_LEGENDARY | SPECIES_FLAG_ULTRA_BURST,
     },
 
     [SPECIES_MAGEARNA_ORIGINAL_COLOR] = MAGEARNA_SPECIES_INFO(BODY_COLOR_RED),

test/battle/form_change/ultra_burst.c

@@ -0,0 +1,127 @@
+#include "global.h"
+#include "test/battle.h"
+
+SINGLE_BATTLE_TEST("Dusk Mane Necrozma can Ultra Burst holding Ultranecrozium Z")
+{
+    GIVEN {
+        ASSUME(P_GEN_7_POKEMON == TRUE);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, player);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+    } THEN {
+        EXPECT_EQ(player->species, SPECIES_NECROZMA_ULTRA);
+    }
+}
+
+DOUBLE_BATTLE_TEST("Ultra Burst's order is determined by Speed - opponent faster")
+{
+    GIVEN {
+        ASSUME(P_GEN_7_POKEMON == TRUE);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(1); }
+        PLAYER(SPECIES_WOBBUFFET) { Speed(3); }
+        OPPONENT(SPECIES_NECROZMA_DAWN_WINGS) { Item(ITEM_ULTRANECROZIUM_Z); Speed(3); }
+        OPPONENT(SPECIES_WOBBUFFET) { Speed(4); }
+    } WHEN {
+        TURN { MOVE(opponentLeft, MOVE_CELEBRATE, ultraBurst: TRUE); MOVE(playerLeft, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Foe Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, opponentLeft);
+        MESSAGE("Foe Necrozma regained its true power through Ultra Burst!");
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, playerLeft);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+    }
+}
+
+DOUBLE_BATTLE_TEST("Ultra Burst's order is determined by Speed - player faster")
+{
+    GIVEN {
+        ASSUME(P_GEN_7_POKEMON == TRUE);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(5); }
+        PLAYER(SPECIES_WOBBUFFET) { Speed(3); }
+        OPPONENT(SPECIES_NECROZMA_DAWN_WINGS) { Item(ITEM_ULTRANECROZIUM_Z); Speed(2); }
+        OPPONENT(SPECIES_WOBBUFFET) { Speed(4); }
+    } WHEN {
+        TURN { MOVE(opponentLeft, MOVE_CELEBRATE, ultraBurst: TRUE); MOVE(playerLeft, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, playerLeft);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+        MESSAGE("Bright light is about to burst out of Foe Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, opponentLeft);
+        MESSAGE("Foe Necrozma regained its true power through Ultra Burst!");
+    }
+}
+
+SINGLE_BATTLE_TEST("Ultra Burst affects turn order")
+{
+    GIVEN {
+        ASSUME(P_GEN_7_POKEMON == TRUE);
+        ASSUME(B_MEGA_EVO_TURN_ORDER);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(105); }
+        OPPONENT(SPECIES_WOBBUFFET) { Speed(106); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE, ultraBurst: TRUE); }
+    } SCENE {
+        MESSAGE("Necrozma used Celebrate!");
+        MESSAGE("Foe Wobbuffet used Celebrate!");
+    } THEN {
+        ASSUME(player->speed == 263);
+    }
+}
+
+DOUBLE_BATTLE_TEST("Ultra Burst happens after switching, but before Focus Punch-like Moves")
+{
+    GIVEN {
+        ASSUME(P_GEN_7_POKEMON == TRUE);
+        ASSUME(gBattleMoves[MOVE_FOCUS_PUNCH].effect == EFFECT_FOCUS_PUNCH);
+        PLAYER(SPECIES_WOBBUFFET);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); }
+        OPPONENT(SPECIES_WYNAUT);
+        OPPONENT(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { SWITCH(opponentRight, 2); MOVE(playerRight, MOVE_FOCUS_PUNCH, ultraBurst: TRUE, target: opponentLeft); MOVE(playerLeft, MOVE_FOCUS_PUNCH, target: opponentLeft); }
+        TURN {}
+    } SCENE {
+        MESSAGE("2 withdrew Wobbuffet!");
+        MESSAGE("2 sent out Wobbuffet!");
+
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, playerRight);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_FOCUS_PUNCH_SETUP, playerRight);
+        MESSAGE("Necrozma is tightening its focus!");
+
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_FOCUS_PUNCH_SETUP, playerLeft);
+        MESSAGE("Wobbuffet is tightening its focus!");
+    }
+}
+
+SINGLE_BATTLE_TEST("Ultra Burst and Mega Evolution can happen on the same turn")
+{
+    GIVEN {
+        ASSUME(P_GEN_7_POKEMON == TRUE);
+        PLAYER(SPECIES_NECROZMA_DUSK_MANE) { Item(ITEM_ULTRANECROZIUM_Z); Speed(3); }
+        OPPONENT(SPECIES_GARDEVOIR) { Item(ITEM_GARDEVOIRITE); Speed(2); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE, ultraBurst: TRUE); MOVE(opponent, MOVE_CELEBRATE, megaEvolve: TRUE); }
+    } SCENE {
+        MESSAGE("Bright light is about to burst out of Necrozma!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ULTRA_BURST, player);
+        MESSAGE("Necrozma regained its true power through Ultra Burst!");
+
+        MESSAGE("Foe Gardevoir's Gardevoirite is reacting to 's Mega Ring!");
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_MEGA_EVOLUTION, opponent);
+        MESSAGE("Foe Gardevoir has Mega Evolved into Mega Gardevoir!");
+    } THEN {
+        EXPECT_EQ(player->species, SPECIES_NECROZMA_ULTRA);
+        EXPECT_EQ(opponent->species, SPECIES_GARDEVOIR_MEGA);
+    }
+}

test/test_runner_battle.c

@@ -1483,6 +1483,9 @@ void Move(u32 sourceLine, struct BattlePokemon *battler, struct MoveContext ctx)
     if (ctx.explicitMegaEvolve && ctx.megaEvolve)
         moveSlot |= RET_MEGA_EVOLUTION;
 
+    if (ctx.explicitUltraBurst && ctx.ultraBurst)
+        moveSlot |= RET_ULTRA_BURST;
+
     if (ctx.explicitTarget)
     {
         target = ctx.target - gBattleMons;