diff --git a/include/battle.h b/include/battle.h
index 9cc78ed41..bc6031665 100644
--- a/include/battle.h
+++ b/include/battle.h
@@ -539,6 +539,7 @@ struct BattleStruct
     u8 lastMoveTarget[MAX_BATTLERS_COUNT]; // The last target on which each mon used a move, for the sake of Instruct
     u8 debugHoldEffects[MAX_BATTLERS_COUNT]; // These override actual items' hold effects.
     u8 tracedAbility[MAX_BATTLERS_COUNT];
+    u16 hpBefore[MAX_BATTLERS_COUNT]; // Hp of battlers before using a move. For Berserk
     bool8 spriteIgnore0Hp;
     struct Illusion illusion[MAX_BATTLERS_COUNT];
 };
diff --git a/src/battle_main.c b/src/battle_main.c
index d860f87cb..d71ad68f9 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -5068,7 +5068,7 @@ void SetTypeBeforeUsingMove(u16 move, u8 battlerAtk)
 
 static void HandleAction_UseMove(void)
 {
-    u32 side, moveType, var = 4;
+    u32 i, side, moveType, var = 4;
 
     gBattlerAttacker = gBattlerByTurnOrder[gCurrentTurnActionNumber];
     if (gBattleStruct->field_91 & gBitTable[gBattlerAttacker] || !IsBattlerAlive(gBattlerAttacker))
@@ -5316,6 +5316,10 @@ static void HandleAction_UseMove(void)
     if (gBattleTypeFlags & BATTLE_TYPE_ARENA)
         BattleArena_AddMindPoints(gBattlerAttacker);
 
+    // Record HP of each battler
+    for (i = 0; i < MAX_BATTLERS_COUNT; i++)
+        gBattleStruct->hpBefore[i] = gBattleMons[i].hp;
+
     gCurrentActionFuncId = B_ACTION_EXEC_SCRIPT;
 }
 
diff --git a/src/battle_util.c b/src/battle_util.c
index 469fc28a0..6b3b03e93 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -3286,6 +3286,23 @@ u8 AbilityBattleEffects(u8 caseID, u8 battler, u8 ability, u8 special, u16 moveA
                 effect++;
             }
             break;
+        case ABILITY_BERSERK:
+            if (!(gMoveResultFlags & MOVE_RESULT_NO_EFFECT)
+             && TARGET_TURN_DAMAGED
+             && IsBattlerAlive(battler)
+            // Had more than half of hp before, now has less
+             && gBattleStruct->hpBefore[battler] > gBattleMons[battler].maxHP / 2
+             && gBattleMons[battler].hp < gBattleMons[battler].maxHP / 2
+             && (gMultiHitCounter == 0 || gMultiHitCounter == 1)
+             && !(GetBattlerAbility(gBattlerAttacker) == ABILITY_SHEER_FORCE && gBattleMoves[gCurrentMove].flags & FLAG_SHEER_FORCE_BOOST)
+             && gBattleMons[battler].statStages[STAT_SPATK] != 12)
+            {
+                SET_STATCHANGER(STAT_SPATK, 1, FALSE);
+                BattleScriptPushCursor();
+                gBattlescriptCurrInstr = BattleScript_TargetAbilityStatRaise;
+                effect++;
+            }
+            break;
         case ABILITY_WEAK_ARMOR:
             if (!(gMoveResultFlags & MOVE_RESULT_NO_EFFECT)
              && TARGET_TURN_DAMAGED