diff --git a/include/battle_util.h b/include/battle_util.h
index 0bf49dadf..0b7b01d0c 100644
--- a/include/battle_util.h
+++ b/include/battle_util.h
@@ -123,7 +123,7 @@ u16 GetMegaEvolutionSpecies(u16 preEvoSpecies, u16 heldItemId);
 u16 GetWishMegaEvolutionSpecies(u16 preEvoSpecies, u16 moveId1, u16 moveId2, u16 moveId3, u16 moveId4);
 bool32 CanMegaEvolve(u8 battlerId);
 void UndoMegaEvolution(u32 monId);
-void UndoFormChange(u32 monId, u32 side);
+void UndoFormChange(u32 monId, u32 side, bool32 isSwitchingOut);
 bool32 DoBattlersShareType(u32 battler1, u32 battler2);
 bool32 CanBattlerGetOrLoseItem(u8 battlerId, u16 itemId);
 struct Pokemon *GetIllusionMonPtr(u32 battlerId);
diff --git a/src/battle_main.c b/src/battle_main.c
index 9cf56abf7..94700bf96 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -3122,7 +3122,7 @@ void FaintClearSetData(void)
     ClearBattlerMoveHistory(gActiveBattler);
     ClearBattlerAbilityHistory(gActiveBattler);
     ClearBattlerItemEffectHistory(gActiveBattler);
-    UndoFormChange(gBattlerPartyIndexes[gActiveBattler], GET_BATTLER_SIDE(gActiveBattler));
+    UndoFormChange(gBattlerPartyIndexes[gActiveBattler], GET_BATTLER_SIDE(gActiveBattler), FALSE);
     if (GetBattlerSide(gActiveBattler) == B_SIDE_PLAYER)
         UndoMegaEvolution(gBattlerPartyIndexes[gActiveBattler]);
 }
@@ -4878,7 +4878,7 @@ static void HandleEndTurn_FinishBattle(void)
         for (i = 0; i < PARTY_SIZE; i++)
         {
             UndoMegaEvolution(i);
-            UndoFormChange(i, B_SIDE_PLAYER);
+            UndoFormChange(i, B_SIDE_PLAYER, FALSE);
         }
         gBattleMainFunc = FreeResetData_ReturnToOvOrDoEvolutions;
         gCB2_AfterEvolution = BattleMainCB2;
diff --git a/src/battle_util.c b/src/battle_util.c
index 87f9003e0..3466a88f9 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -492,7 +492,7 @@ void HandleAction_Switch(void)
     if (gBattleResults.playerSwitchesCounter < 255)
         gBattleResults.playerSwitchesCounter++;
 
-    UndoFormChange(gBattlerPartyIndexes[gBattlerAttacker], GetBattlerSide(gBattlerAttacker));
+    UndoFormChange(gBattlerPartyIndexes[gBattlerAttacker], GetBattlerSide(gBattlerAttacker), TRUE);
 }
 
 void HandleAction_UseItem(void)
@@ -8322,14 +8322,14 @@ void UndoMegaEvolution(u32 monId)
     }
 }
 
-void UndoFormChange(u32 monId, u32 side)
+void UndoFormChange(u32 monId, u32 side, bool32 isSwitchingOut)
 {
     u32 i, currSpecies;
     struct Pokemon *party = (side == B_SIDE_PLAYER) ? gPlayerParty : gEnemyParty;
     static const u16 species[][2] = // changed form id, default form id
     {
-        {SPECIES_AEGISLASH_BLADE, SPECIES_AEGISLASH},
         {SPECIES_MIMIKYU_BUSTED, SPECIES_MIMIKYU},
+        {SPECIES_AEGISLASH_BLADE, SPECIES_AEGISLASH},
         {SPECIES_DARMANITAN_ZEN_MODE, SPECIES_DARMANITAN},
         {SPECIES_MINIOR, SPECIES_MINIOR_CORE_RED},
         {SPECIES_MINIOR_METEOR_BLUE, SPECIES_MINIOR_CORE_BLUE},
@@ -8341,8 +8341,13 @@ void UndoFormChange(u32 monId, u32 side)
         {SPECIES_WISHIWASHI_SCHOOL, SPECIES_WISHIWASHI},
     };
 
+    if (isSwitchingOut) // Don't revert Mimikyu Busted when switching out
+        i = 1;
+    else
+        i = 0;
+
     currSpecies = GetMonData(&party[monId], MON_DATA_SPECIES, NULL);
-    for (i = 0; i < ARRAY_COUNT(species); i++)
+    for (; i < ARRAY_COUNT(species); i++)
     {
         if (currSpecies == species[i][0])
         {