diff --git a/data/battle_anim_scripts.s b/data/battle_anim_scripts.s
index 46719eb3e..863153b9d 100644
--- a/data/battle_anim_scripts.s
+++ b/data/battle_anim_scripts.s
@@ -12057,6 +12057,8 @@ Anim_WishHeal:
 	end
 	
 General_MegaEvolution:
+	createvisualtask sub_815B7D0, 0x2, 0
+	waitforvisualfinish
 	end
 
 AnimScript_82D85A3:
diff --git a/data/battle_scripts_1.s b/data/battle_scripts_1.s
index 0402dc526..dbd076140 100644
--- a/data/battle_scripts_1.s
+++ b/data/battle_scripts_1.s
@@ -4614,9 +4614,9 @@ BattleScript_FocusPunchSetUp::
 BattleScript_MegaEvolution::
 	printstring STRINGID_MEGAEVOREACTING
 	waitmessage 0x40
+	handlemegaevo BS_ATTACKER
 	playanimation BS_ATTACKER, B_ANIM_MEGA_EVOLUTION, NULL
 	waitanimation
-	handlemegaevo BS_ATTACKER
 	printstring STRINGID_MEGAEVOEVOLVED
 	waitmessage 0x40
 	end2
diff --git a/include/battle.h b/include/battle.h
index cedba63c0..ee2323215 100644
--- a/include/battle.h
+++ b/include/battle.h
@@ -602,7 +602,11 @@ struct BattleStruct
     u8 megaEvolvedPartyIds[2]; // As flags using gBitTable;
     bool8 alreadyMegaEvolved[4]; // Array id is used for mon position.
     u16 speciesToMegaEvolve[MAX_BATTLERS_COUNT];
+    u16 playerSpeciesThatMegaEvolved;
     u8 megaEvoBattlerId;
+    bool8 playerMegaEvoSelect;
+    u8 megaEvoTriggerSpriteId;
+    u8 megaEvoIndicatorSpriteId[MAX_BATTLERS_COUNT];
 };
 
 #define GET_MOVE_TYPE(move, typeArg)                        \
diff --git a/include/battle_util.h b/include/battle_util.h
index cf445cfa5..aa69a020b 100644
--- a/include/battle_util.h
+++ b/include/battle_util.h
@@ -89,5 +89,6 @@ u16 CalcPartyMonTypeEffectivenessMultiplier(u16 move, u16 speciesDef, u8 ability
 u16 GetTypeModifier(u8 atkType, u8 defType);
 s32 GetStealthHazardDamage(u8 hazardType, u8 battlerId);
 bool32 CanMegaEvolve(u8 battlerId);
+void UndoMegaEvolution(u8 monId);
 
 #endif // GUARD_BATTLE_UTIL_H
diff --git a/src/battle_controller_player.c b/src/battle_controller_player.c
index 7334b5e79..1e417194d 100644
--- a/src/battle_controller_player.c
+++ b/src/battle_controller_player.c
@@ -386,7 +386,10 @@ static void HandleInputChooseTarget(void)
     {
         PlaySE(SE_SELECT);
         gSprites[gBattlerSpriteIds[gMultiUsePlayerCursor]].callback = sub_8039B2C;
-        BtlController_EmitTwoReturnValues(1, 10, gMoveSelectionCursor[gActiveBattler] | (gMultiUsePlayerCursor << 8));
+        if (gBattleStruct->playerMegaEvoSelect)
+            BtlController_EmitTwoReturnValues(1, 10 | RET_MEGA_EVOLUTION, gMoveSelectionCursor[gActiveBattler] | (gMultiUsePlayerCursor << 8));
+        else
+            BtlController_EmitTwoReturnValues(1, 10, gMoveSelectionCursor[gActiveBattler] | (gMultiUsePlayerCursor << 8));
         EndBounceEffect(gMultiUsePlayerCursor, BOUNCE_HEALTHBOX);
         PlayerBufferExecCompleted();
     }
@@ -540,7 +543,10 @@ static void HandleInputChooseMove(void)
 
         if (!canSelectTarget)
         {
-            BtlController_EmitTwoReturnValues(1, 10, gMoveSelectionCursor[gActiveBattler] | (gMultiUsePlayerCursor << 8));
+            if (gBattleStruct->playerMegaEvoSelect)
+                BtlController_EmitTwoReturnValues(1, 10 | RET_MEGA_EVOLUTION, gMoveSelectionCursor[gActiveBattler] | (gMultiUsePlayerCursor << 8));
+            else
+                BtlController_EmitTwoReturnValues(1, 10, gMoveSelectionCursor[gActiveBattler] | (gMultiUsePlayerCursor << 8));
             PlayerBufferExecCompleted();
         }
         else
@@ -560,6 +566,7 @@ static void HandleInputChooseMove(void)
     else if (gMain.newKeys & B_BUTTON || gPlayerDpadHoldFrames > 59)
     {
         PlaySE(SE_SELECT);
+        gBattleStruct->playerMegaEvoSelect = FALSE;
         BtlController_EmitTwoReturnValues(1, 10, 0xFFFF);
         PlayerBufferExecCompleted();
     }
@@ -629,6 +636,15 @@ static void HandleInputChooseMove(void)
             gBattlerControllerFuncs[gActiveBattler] = HandleMoveSwitchting;
         }
     }
+    else if (gMain.newKeys & START_BUTTON)
+    {
+        if (gBattleStruct->megaEvoTriggerSpriteId != 0xFF)
+        {
+            gBattleStruct->playerMegaEvoSelect ^= 1;
+            // StartSpriteAnim(&gSprites[gBattleStruct->megaEvoTriggerSpriteId], gBattleStruct->playerMegaEvoSelect);
+            PlaySE(SE_SELECT);
+        }
+    }
 }
 
 u32 sub_8057FBC(void) // unused
@@ -2628,6 +2644,11 @@ static void PlayerHandleChooseMove(void)
     {
         InitMoveSelectionsVarsAndStrings();
         gBattlerControllerFuncs[gActiveBattler] = HandleChooseMoveAfterDma3;
+        gBattleStruct->playerMegaEvoSelect = FALSE;
+        if (CanMegaEvolve(gActiveBattler) && gBattleStruct->megaEvoTriggerSpriteId == 0xFF)
+            gBattleStruct->megaEvoTriggerSpriteId = CreateSprite(&gDummySpriteTemplate, 100, 100, 0);
+        else
+            gBattleStruct->megaEvoTriggerSpriteId = 0xFF;
     }
 }
 
diff --git a/src/battle_main.c b/src/battle_main.c
index 1f0dc57fe..50a69ec87 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -3098,6 +3098,10 @@ static void BattleStartClearSetData(void)
 
     gBattleStruct->field_2A0 = 0;
     gBattleStruct->field_2A1 = 0;
+
+    gBattleStruct->megaEvoTriggerSpriteId = 0xFF;
+    for (i = 0; i < MAX_BATTLERS_COUNT; i++)
+        gBattleStruct->megaEvoIndicatorSpriteId[i] = 0xFF;
 }
 
 void SwitchInClearSetData(void)
@@ -3306,6 +3310,8 @@ void FaintClearSetData(void)
 
     ClearBattlerMoveHistory(gActiveBattler);
     ClearBattlerAbilityHistory(gActiveBattler);
+    if (GetBattlerSide(gActiveBattler) == B_SIDE_PLAYER)
+        UndoMegaEvolution(gBattlerPartyIndexes[gActiveBattler]);
 }
 
 static void BattleIntroGetMonsData(void)
@@ -5165,6 +5171,8 @@ static void HandleEndTurn_MonFled(void)
 
 static void HandleEndTurn_FinishBattle(void)
 {
+    u32 i;
+
     if (gCurrentActionFuncId == 0xB || gCurrentActionFuncId == 0xC)
     {
         if (!(gBattleTypeFlags & (BATTLE_TYPE_LINK
@@ -5210,6 +5218,8 @@ static void HandleEndTurn_FinishBattle(void)
         sub_8186444();
         BeginFastPaletteFade(3);
         FadeOutMapMusic(5);
+        for (i = 0; i < PARTY_SIZE; i++)
+            UndoMegaEvolution(i);
         gBattleMainFunc = FreeResetData_ReturnToOvOrDoEvolutions;
         gCB2_AfterEvolution = BattleMainCB2;
     }
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index e23342bb6..e19a08238 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -6599,6 +6599,7 @@ static void atk76_various(void)
         PREPARE_SPECIES_BUFFER(gBattleTextBuff1, gBattleMons[gActiveBattler].species);
 
         CalculateMonStats(mon);
+        gBattleMons[gActiveBattler].level = GetMonData(mon, MON_DATA_LEVEL);
         gBattleMons[gActiveBattler].hp = GetMonData(mon, MON_DATA_HP);
         gBattleMons[gActiveBattler].maxHP = GetMonData(mon, MON_DATA_MAX_HP);
         gBattleMons[gActiveBattler].attack = GetMonData(mon, MON_DATA_ATK);
@@ -6606,6 +6607,9 @@ static void atk76_various(void)
         gBattleMons[gActiveBattler].speed = GetMonData(mon, MON_DATA_SPEED);
         gBattleMons[gActiveBattler].spAttack = GetMonData(mon, MON_DATA_SPATK);
         gBattleMons[gActiveBattler].spDefense = GetMonData(mon, MON_DATA_SPDEF);
+        gBattleMons[gActiveBattler].ability = GetMonAbility(mon);
+        gBattleMons[gActiveBattler].type1 = gBaseStats[gBattleMons[gActiveBattler].species].type1;
+        gBattleMons[gActiveBattler].type2 = gBaseStats[gBattleMons[gActiveBattler].species].type2;
         UpdateHealthboxAttribute(gHealthboxSpriteIds[gActiveBattler], mon, HEALTHBOX_ALL);
 
         gBattleStruct->alreadyMegaEvolved[GetBattlerPosition(gActiveBattler)] = TRUE;
diff --git a/src/battle_util.c b/src/battle_util.c
index c6e40ddb8..2cf0d88ac 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -5600,11 +5600,6 @@ bool32 CanMegaEvolve(u8 battlerId)
         if (IsPartnerMonFromSameTrainer(battlerId) && gBattleStruct->alreadyMegaEvolved[partnerPosition])
             return FALSE;
     }
-    else
-    {
-        if (gBattleStruct->alreadyMegaEvolved[partnerPosition])
-            return FALSE;
-    }
 
     // Check if the pokemon holds an appropriate item,
     if (GetBattlerHoldEffect(battlerId, FALSE) != HOLD_EFFECT_MEGA_STONE)
@@ -5619,6 +5614,9 @@ bool32 CanMegaEvolve(u8 battlerId)
             && gEvolutionTable[species][i].param == itemId)
         {
             gBattleStruct->speciesToMegaEvolve[battlerId] = gEvolutionTable[species][i].targetSpecies;
+            if (battlerPosition == B_POSITION_PLAYER_LEFT
+                || (battlerPosition == B_POSITION_PLAYER_RIGHT && !(gBattleTypeFlags & (BATTLE_TYPE_MULTI | BATTLE_TYPE_INGAME_PARTNER))))
+                gBattleStruct->playerSpeciesThatMegaEvolved = species;
             break;
         }
     }
@@ -5629,3 +5627,13 @@ bool32 CanMegaEvolve(u8 battlerId)
     // All checks passed, the mon CAN mega evolve.
     return TRUE;
 }
+
+void UndoMegaEvolution(u8 monId)
+{
+    if (gBattleStruct->megaEvolvedPartyIds[B_SIDE_PLAYER] & gBitTable[monId])
+    {
+        gBattleStruct->megaEvolvedPartyIds[B_SIDE_PLAYER] &= ~(gBitTable[monId]);
+        SetMonData(&gPlayerParty[monId], MON_DATA_SPECIES, &gBattleStruct->playerSpeciesThatMegaEvolved);
+        CalculateMonStats(&gPlayerParty[monId]);
+    }
+}