diff --git a/src/data/ability.ts b/src/data/ability.ts
index 3245b26f6..39c70fd7e 100644
--- a/src/data/ability.ts
+++ b/src/data/ability.ts
@@ -2104,6 +2104,13 @@ export class StatChangeMultiplierAbAttr extends AbAttr {
   }
 }
 
+export class StatChangeCopyAbAttr extends AbAttr {
+  apply(pokemon: Pokemon, passive: boolean, cancelled: Utils.BooleanHolder, args: any[]): boolean | Promise<boolean> {
+    pokemon.scene.unshiftPhase(new StatChangePhase(pokemon.scene, pokemon.getBattlerIndex(), true, (args[0] as BattleStat[]), (args[1] as integer), true, false, false));
+    return true;
+  }
+}
+
 export class BypassBurnDamageReductionAbAttr extends AbAttr {
   constructor() {
     super(false);
@@ -3484,7 +3491,7 @@ export function initAbilities() {
       .attr(PostBiomeChangeTerrainChangeAbAttr, TerrainType.ELECTRIC)
       .conditionalAttr(getTerrainCondition(TerrainType.ELECTRIC), BattleStatMultiplierAbAttr, BattleStat.SPATK, 4 / 3),
     new Ability(Abilities.OPPORTUNIST, 9)
-      .unimplemented(),
+      .attr(StatChangeCopyAbAttr),
     new Ability(Abilities.CUD_CHEW, 9)
       .unimplemented(),
     new Ability(Abilities.SHARPNESS, 9)
diff --git a/src/phases.ts b/src/phases.ts
index a3b66edf0..67e8cfd54 100644
--- a/src/phases.ts
+++ b/src/phases.ts
@@ -30,7 +30,7 @@ import { Weather, WeatherType, getRandomWeatherType, getTerrainBlockMessage, get
 import { TempBattleStat } from "./data/temp-battle-stat";
 import { ArenaTagSide, ArenaTrapTag, MistTag, TrickRoomTag } from "./data/arena-tag";
 import { ArenaTagType } from "./data/enums/arena-tag-type";
-import { CheckTrappedAbAttr, IgnoreOpponentStatChangesAbAttr, PostAttackAbAttr, PostBattleAbAttr, PostDefendAbAttr, PostSummonAbAttr, PostTurnAbAttr, PostWeatherLapseAbAttr, PreSwitchOutAbAttr, PreWeatherDamageAbAttr, ProtectStatAbAttr, RedirectMoveAbAttr, RunSuccessAbAttr, StatChangeMultiplierAbAttr, SuppressWeatherEffectAbAttr, SyncEncounterNatureAbAttr, applyAbAttrs, applyCheckTrappedAbAttrs, applyPostAttackAbAttrs, applyPostBattleAbAttrs, applyPostDefendAbAttrs, applyPostSummonAbAttrs, applyPostTurnAbAttrs, applyPostWeatherLapseAbAttrs, applyPreStatChangeAbAttrs, applyPreSwitchOutAbAttrs, applyPreWeatherEffectAbAttrs, BattleStatMultiplierAbAttr, applyBattleStatMultiplierAbAttrs, IncrementMovePriorityAbAttr, applyPostVictoryAbAttrs, PostVictoryAbAttr, applyPostBattleInitAbAttrs, PostBattleInitAbAttr, BlockNonDirectDamageAbAttr as BlockNonDirectDamageAbAttr, applyPostKnockOutAbAttrs, PostKnockOutAbAttr, PostBiomeChangeAbAttr, applyPostFaintAbAttrs, PostFaintAbAttr, IncreasePpAbAttr, PostStatChangeAbAttr, applyPostStatChangeAbAttrs, AlwaysHitAbAttr, PreventBerryUseAbAttr } from "./data/ability";
+import { CheckTrappedAbAttr, IgnoreOpponentStatChangesAbAttr, PostAttackAbAttr, PostBattleAbAttr, PostDefendAbAttr, PostSummonAbAttr, PostTurnAbAttr, PostWeatherLapseAbAttr, PreSwitchOutAbAttr, PreWeatherDamageAbAttr, ProtectStatAbAttr, RedirectMoveAbAttr, RunSuccessAbAttr, StatChangeMultiplierAbAttr, SuppressWeatherEffectAbAttr, SyncEncounterNatureAbAttr, applyAbAttrs, applyCheckTrappedAbAttrs, applyPostAttackAbAttrs, applyPostBattleAbAttrs, applyPostDefendAbAttrs, applyPostSummonAbAttrs, applyPostTurnAbAttrs, applyPostWeatherLapseAbAttrs, applyPreStatChangeAbAttrs, applyPreSwitchOutAbAttrs, applyPreWeatherEffectAbAttrs, BattleStatMultiplierAbAttr, applyBattleStatMultiplierAbAttrs, IncrementMovePriorityAbAttr, applyPostVictoryAbAttrs, PostVictoryAbAttr, applyPostBattleInitAbAttrs, PostBattleInitAbAttr, BlockNonDirectDamageAbAttr as BlockNonDirectDamageAbAttr, applyPostKnockOutAbAttrs, PostKnockOutAbAttr, PostBiomeChangeAbAttr, applyPostFaintAbAttrs, PostFaintAbAttr, IncreasePpAbAttr, PostStatChangeAbAttr, applyPostStatChangeAbAttrs, AlwaysHitAbAttr, PreventBerryUseAbAttr, StatChangeCopyAbAttr } from "./data/ability";
 import { Unlockables, getUnlockableName } from "./system/unlockables";
 import { getBiomeKey } from "./field/arena";
 import { BattleType, BattlerIndex, TurnCommand } from "./battle";
@@ -2661,8 +2661,9 @@ export class StatChangePhase extends PokemonPhase {
   private levels: integer;
   private showMessage: boolean;
   private ignoreAbilities: boolean;
+  private canBeCopied: boolean;
 
-  constructor(scene: BattleScene, battlerIndex: BattlerIndex, selfTarget: boolean, stats: BattleStat[], levels: integer, showMessage: boolean = true, ignoreAbilities: boolean = false) {
+  constructor(scene: BattleScene, battlerIndex: BattlerIndex, selfTarget: boolean, stats: BattleStat[], levels: integer, showMessage: boolean = true, ignoreAbilities: boolean = false, canBeCopied: boolean = true) {
     super(scene, battlerIndex);
 
     this.selfTarget = selfTarget;
@@ -2670,6 +2671,7 @@ export class StatChangePhase extends PokemonPhase {
     this.levels = levels;
     this.showMessage = showMessage;
     this.ignoreAbilities = ignoreAbilities;
+    this.canBeCopied = canBeCopied;
   }
 
   start() {
@@ -2717,8 +2719,12 @@ export class StatChangePhase extends PokemonPhase {
       for (let stat of filteredStats)
         pokemon.summonData.battleStats[stat] = Math.max(Math.min(pokemon.summonData.battleStats[stat] + levels.value, 6), -6);
       
+      if (levels.value > 0 && this.canBeCopied)
+        for (let opponent of pokemon.getOpponents())
+          applyAbAttrs(StatChangeCopyAbAttr, opponent, null, this.stats, levels.value);
+      
       applyPostStatChangeAbAttrs(PostStatChangeAbAttr, pokemon, filteredStats, this.levels, this.selfTarget);
-
+      
       pokemon.updateInfo();
 
       handleTutorial(this.scene, Tutorial.Stat_Change).then(() => super.end());