diff --git a/include/battle.h b/include/battle.h
index b328b46bb2..ff5d698abf 100644
--- a/include/battle.h
+++ b/include/battle.h
@@ -472,9 +472,6 @@ struct MegaEvolutionData
     bool8 alreadyEvolved[4]; // Array id is used for mon position.
     u16 evolvedSpecies[MAX_BATTLERS_COUNT];
     u16 playerEvolvedSpecies;
-    u8 primalRevertedPartyIds[2]; // As flags using gBitTable;
-    u16 primalRevertedSpecies[MAX_BATTLERS_COUNT];
-    u16 playerPrimalRevertedSpecies;
     u8 battlerId;
     bool8 playerSelect;
     u8 triggerSpriteId;
diff --git a/include/battle_util.h b/include/battle_util.h
index fb5090f348..5a09909509 100644
--- a/include/battle_util.h
+++ b/include/battle_util.h
@@ -145,11 +145,12 @@ u16 CalcPartyMonTypeEffectivenessMultiplier(u16 move, u16 speciesDef, u16 abilit
 u16 GetTypeModifier(u8 atkType, u8 defType);
 s32 GetStealthHazardDamage(u8 hazardType, u8 battlerId);
 u16 GetMegaEvolutionSpecies(u16 preEvoSpecies, u16 heldItemId);
-u16 GetPrimalReversionSpecies(u16 preEvoSpecies, u16 heldItemId);
+u16 GetPrimalReversionSpecies(u16 preSpecies, u16 heldItemId);
 u16 GetWishMegaEvolutionSpecies(u16 preEvoSpecies, u16 moveId1, u16 moveId2, u16 moveId3, u16 moveId4);
 bool32 CanMegaEvolve(u8 battlerId);
 void UndoMegaEvolution(u32 monId);
-void BattleFormChange(u32 monId, u32 side, u16 method);
+bool32 IsBattlerPrimalReverted(u8 battlerId);
+void TryBattleFormChange(u8 battlerId, u16 method);
 bool32 DoBattlersShareType(u32 battler1, u32 battler2);
 bool32 CanBattlerGetOrLoseItem(u8 battlerId, u16 itemId);
 struct Pokemon *GetIllusionMonPtr(u32 battlerId);
@@ -186,6 +187,7 @@ void TryToRevertMimicry(void);
 void RestoreBattlerOriginalTypes(u8 battlerId);
 u32 GetBattlerMoveTargetType(u8 battlerId, u16 move);
 bool32 CanTargetBattler(u8 battlerAtk, u8 battlerDef, u16 move);
+void RecalcBattlerStats(u32 battler, struct Pokemon *mon);
 // Ability checks
 bool32 IsRolePlayBannedAbilityAtk(u16 ability);
 bool32 IsRolePlayBannedAbility(u16 ability);
diff --git a/include/constants/pokemon.h b/include/constants/pokemon.h
index bb77398dd5..7dc250834e 100644
--- a/include/constants/pokemon.h
+++ b/include/constants/pokemon.h
@@ -266,7 +266,6 @@
 // Evolution types
 #define EVO_MEGA_EVOLUTION                0xffff // Not an actual evolution, used to temporarily mega evolve in battle.
 #define EVO_MOVE_MEGA_EVOLUTION           0xfffe // Mega Evolution that checks for a move instead of held item.
-#define EVO_PRIMAL_REVERSION              0xfffd // Not an actual evolution, used to undergo primal reversion in battle.
 #define EVO_FRIENDSHIP                    1      // Pokémon levels up with friendship ≥ 220
 #define EVO_FRIENDSHIP_DAY                2      // Pokémon levels up during the day with friendship ≥ 220
 #define EVO_FRIENDSHIP_NIGHT              3      // Pokémon levels up at night with friendship ≥ 220
@@ -317,15 +316,16 @@
 #define EVO_MODE_OVERWORLD_SPECIAL 5
 
 // Form change types
-#define FORM_CHANGE_END             0
-#define FORM_CHANGE_ITEM_HOLD       1
-#define FORM_CHANGE_ITEM_USE        2
-#define FORM_CHANGE_MOVE            3
-#define FORM_CHANGE_WITHDRAW        4
-#define FORM_CHANGE_BATTLE_BEGIN    5
-#define FORM_CHANGE_BATTLE_SWITCH   6
-#define FORM_CHANGE_BATTLE_FAINT    7
-#define FORM_CHANGE_BATTLE_END      8
+#define FORM_CHANGE_END                 0 // Form table terminator
+#define FORM_CHANGE_ITEM_HOLD           1
+#define FORM_CHANGE_ITEM_USE            2
+#define FORM_CHANGE_MOVE                3 // Todo
+#define FORM_CHANGE_WITHDRAW            4 // 
+#define FORM_CHANGE_BATTLE_BEGIN        5
+#define FORM_CHANGE_BATTLE_END          6
+#define FORM_CHANGE_BATTLE_SWITCH       7
+#define FORM_CHANGE_BATTLE_FAINT        8
+#define FORM_CHANGE_PRIMAL_REVERSION    9
 
 #define MON_PIC_WIDTH 64
 #define MON_PIC_HEIGHT 64
@@ -345,14 +345,15 @@
 #define SPECIES_FLAG_LEGENDARY          (1 << 0)
 #define SPECIES_FLAG_MYTHICAL           (1 << 1)
 #define SPECIES_FLAG_MEGA_EVOLUTION     (1 << 2)
-#define SPECIES_FLAG_ULTRA_BEAST        (1 << 3)
-#define SPECIES_FLAG_ALOLAN_FORM        (1 << 4)
-#define SPECIES_FLAG_GALARIAN_FORM      (1 << 5)
-#define SPECIES_FLAG_HISUIAN_FORM       (1 << 6)
-#define SPECIES_FLAG_GENDER_DIFFERENCE  (1 << 7)
-#define SPECIES_FLAG_ALL_PERFECT_IVS    (1 << 8)
-#define SPECIES_FLAG_SHINY_LOCKED       (1 << 9)
-#define SPECIES_FLAG_CANNOT_BE_TRADED   (1 << 10)
+#define SPECIES_FLAG_PRIMAL_REVERSION   (1 << 3)
+#define SPECIES_FLAG_ULTRA_BEAST        (1 << 4)
+#define SPECIES_FLAG_ALOLAN_FORM        (1 << 5)
+#define SPECIES_FLAG_GALARIAN_FORM      (1 << 6)
+#define SPECIES_FLAG_HISUIAN_FORM       (1 << 7)
+#define SPECIES_FLAG_GENDER_DIFFERENCE  (1 << 8)
+#define SPECIES_FLAG_ALL_PERFECT_IVS    (1 << 9)
+#define SPECIES_FLAG_SHINY_LOCKED       (1 << 10)
+#define SPECIES_FLAG_CANNOT_BE_TRADED   (1 << 11)
 
 #define LEGENDARY_PERFECT_IV_COUNT 3
 
diff --git a/include/pokemon.h b/include/pokemon.h
index fa5bfc663e..134991b953 100644
--- a/include/pokemon.h
+++ b/include/pokemon.h
@@ -409,6 +409,7 @@ extern const u16 gUnionRoomFacilityClasses[];
 extern const struct SpriteTemplate gBattlerSpriteTemplates[];
 extern const s8 gNatureStatTable[][5];
 extern const u16 *const gFormSpeciesIdTables[NUM_SPECIES];
+extern const struct FormChange *const gFormChangeTablePointers[NUM_SPECIES];
 extern const u32 sExpCandyExperienceTable[];
 
 void ZeroBoxMonData(struct BoxPokemon *boxMon);
@@ -564,6 +565,7 @@ u16 GetFormChangeTargetSpecies(struct Pokemon *mon, u16 method, u32 arg);
 u16 GetFormChangeTargetSpeciesBoxMon(struct BoxPokemon *mon, u16 method, u32 arg);
 u16 MonTryLearningNewMoveEvolution(struct Pokemon *mon, bool8 firstMove);
 bool32 ShouldShowFemaleDifferences(u16 species, u32 personality);
+void TryFormChange(u32 monId, u32 side, u16 method);
 void TryToSetBattleFormChangeMoves(struct Pokemon *mon, u16 method);
 u32 GetMonFriendshipScore(struct Pokemon *pokemon);
 
diff --git a/src/battle_interface.c b/src/battle_interface.c
index 3039c65b67..ed756592f8 100644
--- a/src/battle_interface.c
+++ b/src/battle_interface.c
@@ -871,8 +871,8 @@ u8 CreateBattlerHealthboxSprites(u8 battlerId)
     healthBarSpritePtr->invisible = TRUE;
 
     // Create mega indicator sprite if is a mega evolved or a primal reverted mon.
-    if (gBattleStruct->mega.evolvedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]]
-     || gBattleStruct->mega.primalRevertedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]])
+    if ((gBattleStruct->mega.evolvedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]])
+     || IsBattlerPrimalReverted(battlerId))
     {
         megaIndicatorSpriteId = CreateMegaIndicatorSprite(battlerId, 0);
         gSprites[megaIndicatorSpriteId].invisible = TRUE;
@@ -979,8 +979,8 @@ void SetHealthboxSpriteVisible(u8 healthboxSpriteId)
     gSprites[healthboxSpriteId].invisible = FALSE;
     gSprites[gSprites[healthboxSpriteId].hMain_HealthBarSpriteId].invisible = FALSE;
     gSprites[gSprites[healthboxSpriteId].oam.affineParam].invisible = FALSE;
-    if (gBattleStruct->mega.evolvedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]]
-     || gBattleStruct->mega.primalRevertedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]])
+    if ((gBattleStruct->mega.evolvedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]])
+     || IsBattlerPrimalReverted(battlerId))
     {
         u8 spriteId = GetMegaIndicatorSpriteId(healthboxSpriteId);
         if (spriteId != 0xFF)
@@ -1104,8 +1104,8 @@ static void UpdateLvlInHealthbox(u8 healthboxSpriteId, u8 lvl)
     u8 battler = gSprites[healthboxSpriteId].hMain_Battler;
 
     // Don't print Lv char if mon is mega evolved or primal reverted.
-    if (gBattleStruct->mega.evolvedPartyIds[GetBattlerSide(battler)] & gBitTable[gBattlerPartyIndexes[battler]]
-     || gBattleStruct->mega.primalRevertedPartyIds[GetBattlerSide(battler)] & gBitTable[gBattlerPartyIndexes[battler]])
+    if ((gBattleStruct->mega.evolvedPartyIds[GetBattlerSide(battler)] & gBitTable[gBattlerPartyIndexes[battler]])
+     || IsBattlerPrimalReverted(battler))
     {
         objVram = ConvertIntToDecimalStringN(text, lvl, STR_CONV_MODE_LEFT_ALIGN, 3);
         xPos = 5 * (3 - (objVram - (text + 2))) - 1;
@@ -1561,7 +1561,7 @@ u32 CreateMegaIndicatorSprite(u32 battlerId, u32 which)
         LoadSpritePalette(&sSpritePalette_MegaIndicator);
         LoadSpriteSheet(&sSpriteSheet_MegaIndicator);
     }
-    else if (gBattleStruct->mega.primalRevertedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]])
+    else if (IsBattlerPrimalReverted(battlerId))
     {
         if (GET_BASE_SPECIES_ID(gBattleMons[battlerId].species) == SPECIES_GROUDON)
         {
@@ -1590,7 +1590,7 @@ u32 CreateMegaIndicatorSprite(u32 battlerId, u32 which)
     {
         spriteId = CreateSpriteAtEnd(&sSpriteTemplate_MegaIndicator, x, y, 0);
     }
-    else if (gBattleStruct->mega.primalRevertedPartyIds[GetBattlerSide(battlerId)] & gBitTable[gBattlerPartyIndexes[battlerId]])
+    else if (IsBattlerPrimalReverted(battlerId))
     {
         if (GET_BASE_SPECIES_ID(gBattleMons[battlerId].species) == SPECIES_GROUDON)
             spriteId = CreateSpriteAtEnd(&sSpriteTemplate_OmegaIndicator, x, y, 0);
diff --git a/src/battle_main.c b/src/battle_main.c
index 71d263860e..f58c0d43bb 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -602,9 +602,9 @@ static void CB2_InitBattleInternal(void)
     for (i = 0; i < PARTY_SIZE; i++)
     {
         // Player's side
-        BattleFormChange(i, B_SIDE_PLAYER, FORM_CHANGE_BATTLE_BEGIN);
+        TryFormChange(i, B_SIDE_PLAYER, FORM_CHANGE_BATTLE_BEGIN);
         // Opponent's side
-        BattleFormChange(i, B_SIDE_OPPONENT, FORM_CHANGE_BATTLE_BEGIN);
+        TryFormChange(i, B_SIDE_OPPONENT, FORM_CHANGE_BATTLE_BEGIN);
     }
 
     gBattleCommunication[MULTIUSE_STATE] = 0;
@@ -3247,7 +3247,7 @@ void FaintClearSetData(void)
     gBattleMons[gActiveBattler].type3 = TYPE_MYSTERY;
 
     Ai_UpdateFaintData(gActiveBattler);
-    BattleFormChange(gBattlerPartyIndexes[gActiveBattler], GET_BATTLER_SIDE(gActiveBattler), FORM_CHANGE_BATTLE_FAINT);
+    TryFormChange(gBattlerPartyIndexes[gActiveBattler], GET_BATTLER_SIDE(gActiveBattler), FORM_CHANGE_BATTLE_FAINT);
     if (GetBattlerSide(gActiveBattler) == B_SIDE_PLAYER)
         UndoMegaEvolution(gBattlerPartyIndexes[gActiveBattler]);
 
@@ -3682,18 +3682,12 @@ static void TryDoEventsBeforeFirstTurn(void)
     // Primal Reversion
     for (i = 0; i < gBattlersCount; i++)
     {
-        if (GetBattlerHoldEffect(i, TRUE) == HOLD_EFFECT_PRIMAL_ORB)
+        if (GetBattlerHoldEffect(i, TRUE) == HOLD_EFFECT_PRIMAL_ORB
+            && GetPrimalReversionSpecies(gBattleMons[i].species, gBattleMons[i].item) != SPECIES_NONE)
         {
-            for (j = 0; j < EVOS_PER_MON; j++)
-            {
-                if (gEvolutionTable[gBattleMons[i].species][j].targetSpecies != SPECIES_NONE
-                 && gEvolutionTable[gBattleMons[i].species][j].method == EVO_PRIMAL_REVERSION)
-                {
-                    gBattlerAttacker = i;
-                    BattleScriptExecute(BattleScript_PrimalReversion);
-                    return;
-                }
-            }
+            gBattlerAttacker = i;
+            BattleScriptExecute(BattleScript_PrimalReversion);
+            return;
         }
     }
 
@@ -5207,7 +5201,7 @@ static void HandleEndTurn_FinishBattle(void)
         for (i = 0; i < PARTY_SIZE; i++)
         {
             UndoMegaEvolution(i);
-            BattleFormChange(i, B_SIDE_PLAYER, FORM_CHANGE_BATTLE_END);
+            TryFormChange(i, B_SIDE_PLAYER, FORM_CHANGE_BATTLE_END);
             DoBurmyFormChange(i);
         }
     #if B_RECALCULATE_STATS >= GEN_5
@@ -5221,6 +5215,13 @@ static void HandleEndTurn_FinishBattle(void)
             }
         }
     #endif
+        // Clear battle mon species to avoid a bug on the next battle that causes
+        // healthboxes loading incorrectly due to it trying to create a Mega Indicator
+        // if the previous battler would've had.
+        for (i = 0; i < MAX_BATTLERS_COUNT; i++)
+        {
+            gBattleMons[i].species = SPECIES_NONE;
+        }
         gBattleMainFunc = FreeResetData_ReturnToOvOrDoEvolutions;
         gCB2_AfterEvolution = BattleMainCB2;
     }
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index 060a9e7170..51d3cfbe16 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -7914,22 +7914,6 @@ u32 IsAbilityStatusProtected(u32 battler)
         || IsShieldsDownProtected(battler);
 }
 
-static void RecalcBattlerStats(u32 battler, struct Pokemon *mon)
-{
-    CalculateMonStats(mon);
-    gBattleMons[battler].level = GetMonData(mon, MON_DATA_LEVEL);
-    gBattleMons[battler].hp = GetMonData(mon, MON_DATA_HP);
-    gBattleMons[battler].maxHP = GetMonData(mon, MON_DATA_MAX_HP);
-    gBattleMons[battler].attack = GetMonData(mon, MON_DATA_ATK);
-    gBattleMons[battler].defense = GetMonData(mon, MON_DATA_DEF);
-    gBattleMons[battler].speed = GetMonData(mon, MON_DATA_SPEED);
-    gBattleMons[battler].spAttack = GetMonData(mon, MON_DATA_SPATK);
-    gBattleMons[battler].spDefense = GetMonData(mon, MON_DATA_SPDEF);
-    gBattleMons[battler].ability = GetMonAbility(mon);
-    gBattleMons[battler].type1 = gBaseStats[gBattleMons[battler].species].type1;
-    gBattleMons[battler].type2 = gBaseStats[gBattleMons[battler].species].type2;
-}
-
 static u32 GetHighestStatId(u32 battlerId)
 {
     u32 i, highestId = STAT_ATK, highestStat = gBattleMons[battlerId].attack;
@@ -8870,17 +8854,7 @@ static void Cmd_various(void)
         // Change species.
         if (gBattlescriptCurrInstr[3] == 0)
         {
-            u16 primalSpecies;
-            gBattleStruct->mega.primalRevertedSpecies[gActiveBattler] = gBattleMons[gActiveBattler].species;
-            if (GetBattlerPosition(gActiveBattler) == B_POSITION_PLAYER_LEFT
-                || (GetBattlerPosition(gActiveBattler) == B_POSITION_PLAYER_RIGHT && !(gBattleTypeFlags & (BATTLE_TYPE_MULTI | BATTLE_TYPE_INGAME_PARTNER))))
-            {
-                gBattleStruct->mega.playerPrimalRevertedSpecies = gBattleStruct->mega.primalRevertedSpecies[gActiveBattler];
-            }
-            // Checks Primal Reversion
-            primalSpecies = GetPrimalReversionSpecies(gBattleStruct->mega.primalRevertedSpecies[gActiveBattler], gBattleMons[gActiveBattler].item);
-
-            gBattleMons[gActiveBattler].species = primalSpecies;
+            gBattleMons[gActiveBattler].species = GetPrimalReversionSpecies(gBattleMons[gActiveBattler].species, gBattleMons[gActiveBattler].item);
             PREPARE_SPECIES_BUFFER(gBattleTextBuff1, gBattleMons[gActiveBattler].species);
 
             BtlController_EmitSetMonData(BUFFER_A, REQUEST_SPECIES_BATTLE, gBitTable[gBattlerPartyIndexes[gActiveBattler]], sizeof(gBattleMons[gActiveBattler].species), &gBattleMons[gActiveBattler].species);
@@ -8890,7 +8864,6 @@ static void Cmd_various(void)
         else if (gBattlescriptCurrInstr[3] == 1)
         {
             RecalcBattlerStats(gActiveBattler, mon);
-            gBattleStruct->mega.primalRevertedPartyIds[GetBattlerSide(gActiveBattler)] |= gBitTable[gBattlerPartyIndexes[gActiveBattler]];
         }
         // Update healthbox and elevation.
         else
@@ -9606,15 +9579,7 @@ static void Cmd_various(void)
         return;
     case VARIOUS_JUMP_IF_CANT_REVERT_TO_PRIMAL:
     {
-        bool8 canDoPrimalReversion = FALSE;
-
-        for (i = 0; i < EVOS_PER_MON; i++)
-        {
-            if (gEvolutionTable[gBattleMons[gActiveBattler].species][i].method == EVO_PRIMAL_REVERSION
-            && gEvolutionTable[gBattleMons[gActiveBattler].species][i].param == gBattleMons[gActiveBattler].item)
-                canDoPrimalReversion = TRUE;
-        }
-        if (!canDoPrimalReversion)
+        if (GetPrimalReversionSpecies(gBattleMons[gActiveBattler].species, gBattleMons[gActiveBattler].item) == SPECIES_NONE)
             gBattlescriptCurrInstr = T1_READ_PTR(gBattlescriptCurrInstr + 3);
         else
             gBattlescriptCurrInstr += 7;
@@ -14109,7 +14074,7 @@ static void Cmd_handleballthrow(void)
         {
             BtlController_EmitBallThrowAnim(BUFFER_A, BALL_3_SHAKES_SUCCESS);
             MarkBattlerForControllerExec(gActiveBattler);
-            BattleFormChange(gBattlerPartyIndexes[gBattlerTarget], GET_BATTLER_SIDE(gBattlerTarget), FORM_CHANGE_BATTLE_END),
+            TryFormChange(gBattlerPartyIndexes[gBattlerTarget], GET_BATTLER_SIDE(gBattlerTarget), FORM_CHANGE_BATTLE_END),
             gBattlescriptCurrInstr = BattleScript_SuccessBallThrow;
             SetMonData(&gEnemyParty[gBattlerPartyIndexes[gBattlerTarget]], MON_DATA_POKEBALL, &gLastUsedItem);
 
@@ -14163,7 +14128,7 @@ static void Cmd_handleballthrow(void)
                 if (IsCriticalCapture())
                     gBattleSpritesDataPtr->animationData->criticalCaptureSuccess = TRUE;
 
-                BattleFormChange(gBattlerPartyIndexes[gBattlerTarget], GET_BATTLER_SIDE(gBattlerTarget), FORM_CHANGE_BATTLE_END),
+                TryFormChange(gBattlerPartyIndexes[gBattlerTarget], GET_BATTLER_SIDE(gBattlerTarget), FORM_CHANGE_BATTLE_END),
                 gBattlescriptCurrInstr = BattleScript_SuccessBallThrow;
                 SetMonData(&gEnemyParty[gBattlerPartyIndexes[gBattlerTarget]], MON_DATA_POKEBALL, &gLastUsedItem);
 
diff --git a/src/battle_util.c b/src/battle_util.c
index f39d2a03e5..729728ec0e 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -518,7 +518,7 @@ void HandleAction_Switch(void)
     if (gBattleResults.playerSwitchesCounter < 255)
         gBattleResults.playerSwitchesCounter++;
 
-    BattleFormChange(gBattlerPartyIndexes[gBattlerAttacker], GetBattlerSide(gBattlerAttacker), FORM_CHANGE_BATTLE_SWITCH);
+    TryFormChange(gBattlerPartyIndexes[gBattlerAttacker], GetBattlerSide(gBattlerAttacker), FORM_CHANGE_BATTLE_SWITCH);
 }
 
 void HandleAction_UseItem(void)
@@ -8955,8 +8955,7 @@ static bool32 CanEvolve(u32 species)
     {
         if (gEvolutionTable[species][i].method
          && gEvolutionTable[species][i].method != EVO_MEGA_EVOLUTION
-         && gEvolutionTable[species][i].method != EVO_MOVE_MEGA_EVOLUTION
-         && gEvolutionTable[species][i].method != EVO_PRIMAL_REVERSION)
+         && gEvolutionTable[species][i].method != EVO_MOVE_MEGA_EVOLUTION)
             return TRUE;
     }
     return FALSE;
@@ -9565,15 +9564,20 @@ u16 GetMegaEvolutionSpecies(u16 preEvoSpecies, u16 heldItemId)
     return SPECIES_NONE;
 }
 
-u16 GetPrimalReversionSpecies(u16 preEvoSpecies, u16 heldItemId)
+u16 GetPrimalReversionSpecies(u16 preSpecies, u16 heldItemId)
 {
     u32 i;
+    const struct FormChange *formChanges = gFormChangeTablePointers[preSpecies];
 
-    for (i = 0; i < EVOS_PER_MON; i++)
+    if (formChanges != NULL)
     {
-        if (gEvolutionTable[preEvoSpecies][i].method == EVO_PRIMAL_REVERSION
-         && gEvolutionTable[preEvoSpecies][i].param == heldItemId)
-            return gEvolutionTable[preEvoSpecies][i].targetSpecies;
+        for (i = 0; formChanges[i].method != FORM_CHANGE_END; i++)
+        {
+            if (formChanges[i].method == FORM_CHANGE_PRIMAL_REVERSION
+             && formChanges[i].param1 == heldItemId
+             && formChanges[i].targetSpecies != preSpecies)
+                return formChanges[i].targetSpecies;
+        }
     }
     return SPECIES_NONE;
 }
@@ -9675,12 +9679,6 @@ void UndoMegaEvolution(u32 monId)
         SetMonData(&gPlayerParty[monId], MON_DATA_SPECIES, &gBattleStruct->mega.playerEvolvedSpecies);
         CalculateMonStats(&gPlayerParty[monId]);
     }
-    else if (gBattleStruct->mega.primalRevertedPartyIds[B_SIDE_PLAYER] & gBitTable[monId])
-    {
-        gBattleStruct->mega.primalRevertedPartyIds[B_SIDE_PLAYER] &= ~(gBitTable[monId]);
-        SetMonData(&gPlayerParty[monId], MON_DATA_SPECIES, &baseSpecies);
-        CalculateMonStats(&gPlayerParty[monId]);
-    }
     // While not exactly a mega evolution, Zygarde follows the same rules.
     else if (GetMonData(&gPlayerParty[monId], MON_DATA_SPECIES, NULL) == SPECIES_ZYGARDE_COMPLETE)
     {
@@ -9690,17 +9688,23 @@ void UndoMegaEvolution(u32 monId)
     }
 }
 
-void BattleFormChange(u32 monId, u32 side, u16 method)
+bool32 IsBattlerPrimalReverted(u8 battlerId)
 {
-    u32 targetSpecies;
+    return (gBaseStats[gBattleMons[battlerId].species].flags & SPECIES_FLAG_PRIMAL_REVERSION);
+}
+
+void TryBattleFormChange(u8 battlerId, u16 method)
+{
+    u16 targetSpecies;
+    u8 monId = gBattlerPartyIndexes[battlerId];
+    u8 side = GET_BATTLER_SIDE(battlerId);
     struct Pokemon *party = (side == B_SIDE_PLAYER) ? gPlayerParty : gEnemyParty;
 
     targetSpecies = GetFormChangeTargetSpecies(&party[monId], method, 0);
     if (targetSpecies != SPECIES_NONE)
     {
-        TryToSetBattleFormChangeMoves(&party[monId], method);
         SetMonData(&party[monId], MON_DATA_SPECIES, &targetSpecies);
-        CalculateMonStats(&party[monId]);
+        RecalcBattlerStats(battlerId, &party[monId]);
     }
 }
 
@@ -10362,3 +10366,19 @@ bool32 CanTargetBattler(u8 battlerAtk, u8 battlerDef, u16 move)
         return FALSE;   // Pokémon affected by Heal Block cannot target allies with Pollen Puff
     return TRUE;
 }
+
+void RecalcBattlerStats(u32 battler, struct Pokemon *mon)
+{
+    CalculateMonStats(mon);
+    gBattleMons[battler].level = GetMonData(mon, MON_DATA_LEVEL);
+    gBattleMons[battler].hp = GetMonData(mon, MON_DATA_HP);
+    gBattleMons[battler].maxHP = GetMonData(mon, MON_DATA_MAX_HP);
+    gBattleMons[battler].attack = GetMonData(mon, MON_DATA_ATK);
+    gBattleMons[battler].defense = GetMonData(mon, MON_DATA_DEF);
+    gBattleMons[battler].speed = GetMonData(mon, MON_DATA_SPEED);
+    gBattleMons[battler].spAttack = GetMonData(mon, MON_DATA_SPATK);
+    gBattleMons[battler].spDefense = GetMonData(mon, MON_DATA_SPDEF);
+    gBattleMons[battler].ability = GetMonAbility(mon);
+    gBattleMons[battler].type1 = gBaseStats[gBattleMons[battler].species].type1;
+    gBattleMons[battler].type2 = gBaseStats[gBattleMons[battler].species].type2;
+}
diff --git a/src/data/pokemon/base_stats.h b/src/data/pokemon/base_stats.h
index a161fbf908..a13ea59391 100644
--- a/src/data/pokemon/base_stats.h
+++ b/src/data/pokemon/base_stats.h
@@ -24117,7 +24117,7 @@ const struct BaseStats gBaseStats[] =
         .abilities = {ABILITY_PRIMORDIAL_SEA, ABILITY_PRIMORDIAL_SEA},
         .bodyColor = BODY_COLOR_BLUE,
         .noFlip = FALSE,
-        .flags = SPECIES_FLAG_LEGENDARY,
+        .flags = SPECIES_FLAG_LEGENDARY | SPECIES_FLAG_PRIMAL_REVERSION,
     },
 
     [SPECIES_GROUDON_PRIMAL] =
@@ -24142,7 +24142,7 @@ const struct BaseStats gBaseStats[] =
         .abilities = {ABILITY_DESOLATE_LAND, ABILITY_DESOLATE_LAND},
         .bodyColor = BODY_COLOR_RED,
         .noFlip = FALSE,
-        .flags = SPECIES_FLAG_LEGENDARY,
+        .flags = SPECIES_FLAG_LEGENDARY | SPECIES_FLAG_PRIMAL_REVERSION,
     },
 
     [SPECIES_RATTATA_ALOLAN] =
diff --git a/src/data/pokemon/evolution.h b/src/data/pokemon/evolution.h
index 4f09867a6c..0aaf8f90c7 100644
--- a/src/data/pokemon/evolution.h
+++ b/src/data/pokemon/evolution.h
@@ -293,8 +293,6 @@ const struct Evolution gEvolutionTable[NUM_SPECIES][EVOS_PER_MON] =
     [SPECIES_METAGROSS]             = {{EVO_MEGA_EVOLUTION, ITEM_METAGROSSITE, SPECIES_METAGROSS_MEGA}},
     [SPECIES_LATIAS]                = {{EVO_MEGA_EVOLUTION, ITEM_LATIASITE, SPECIES_LATIAS_MEGA}},
     [SPECIES_LATIOS]                = {{EVO_MEGA_EVOLUTION, ITEM_LATIOSITE, SPECIES_LATIOS_MEGA}},
-    [SPECIES_KYOGRE]                = {{EVO_PRIMAL_REVERSION, ITEM_BLUE_ORB, SPECIES_KYOGRE_PRIMAL}},
-    [SPECIES_GROUDON]               = {{EVO_PRIMAL_REVERSION, ITEM_RED_ORB, SPECIES_GROUDON_PRIMAL}},
     [SPECIES_RAYQUAZA]              = {{EVO_MOVE_MEGA_EVOLUTION, MOVE_DRAGON_ASCENT, SPECIES_RAYQUAZA_MEGA}},
 
 #if P_GEN_4_POKEMON == TRUE
diff --git a/src/data/pokemon/form_change_table_pointers.h b/src/data/pokemon/form_change_table_pointers.h
index 63971f1325..a0cc805e9a 100644
--- a/src/data/pokemon/form_change_table_pointers.h
+++ b/src/data/pokemon/form_change_table_pointers.h
@@ -1,5 +1,9 @@
 const struct FormChange *const gFormChangeTablePointers[NUM_SPECIES] =
 {
+    [SPECIES_KYOGRE] = sKyogreFormChangeTable,
+    [SPECIES_KYOGRE_PRIMAL] = sKyogreFormChangeTable,
+    [SPECIES_GROUDON] = sGroudonFormChangeTable,
+    [SPECIES_GROUDON_PRIMAL] = sGroudonFormChangeTable,
 #if P_GEN_4_POKEMON == TRUE
     [SPECIES_GIRATINA] = sGiratinaFormChangeTable,
     [SPECIES_GIRATINA_ORIGIN] = sGiratinaFormChangeTable,
diff --git a/src/data/pokemon/form_change_tables.h b/src/data/pokemon/form_change_tables.h
index 0586c8ac88..7342256ecd 100644
--- a/src/data/pokemon/form_change_tables.h
+++ b/src/data/pokemon/form_change_tables.h
@@ -47,6 +47,18 @@ FORM_CHANGE_BATTLE_END:
 #define DAY    1
 #define NIGHT  2
 
+static const struct FormChange sKyogreFormChangeTable[] = {
+    {FORM_CHANGE_PRIMAL_REVERSION,  SPECIES_KYOGRE_PRIMAL, ITEM_BLUE_ORB},
+    {FORM_CHANGE_BATTLE_END,        SPECIES_KYOGRE},
+    {FORM_CHANGE_END},
+};
+
+static const struct FormChange sGroudonFormChangeTable[] = {
+    {FORM_CHANGE_PRIMAL_REVERSION,  SPECIES_GROUDON_PRIMAL, ITEM_RED_ORB},
+    {FORM_CHANGE_BATTLE_END,        SPECIES_GROUDON},
+    {FORM_CHANGE_END},
+};
+
 #if P_GEN_4_POKEMON == TRUE
 static const struct FormChange sGiratinaFormChangeTable[] = {
     {FORM_CHANGE_ITEM_HOLD, SPECIES_GIRATINA, ITEM_NONE},
@@ -178,7 +190,7 @@ static const struct FormChange sXerneasFormChangeTable[] = {
 
 static const struct FormChange sHoopaFormChangeTable[] = {
     {FORM_CHANGE_ITEM_USE, SPECIES_HOOPA_UNBOUND, ITEM_PRISON_BOTTLE, SPECIES_HOOPA},
-    // {FORM_CHANGE_WITHDRAW, SPECIES_HOOPA},
+    {FORM_CHANGE_WITHDRAW, SPECIES_HOOPA},
     {FORM_CHANGE_END},
 };
 #endif
diff --git a/src/pokemon.c b/src/pokemon.c
index b60e5a30ee..ced0f67b9d 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -8397,6 +8397,16 @@ u16 GetFormChangeTargetSpeciesBoxMon(struct BoxPokemon *boxMon, u16 method, u32
                 case FORM_CHANGE_BATTLE_END:
                     if (heldItem == formChanges[i].param1 || formChanges[i].param1 == ITEM_NONE)
                         targetSpecies = formChanges[i].targetSpecies;
+                    break;
+                case FORM_CHANGE_PRIMAL_REVERSION:
+                    if (arg == formChanges[i].param1)
+                        targetSpecies = formChanges[i].targetSpecies;
+                    break;
+                case FORM_CHANGE_WITHDRAW:
+                case FORM_CHANGE_BATTLE_SWITCH:
+                case FORM_CHANGE_BATTLE_FAINT:
+                    targetSpecies = formChanges[i].targetSpecies;
+                    break;
                 }
             }
         }
@@ -8485,13 +8495,28 @@ bool32 ShouldShowFemaleDifferences(u16 species, u32 personality)
     return (gBaseStats[species].flags & SPECIES_FLAG_GENDER_DIFFERENCE) && GetGenderFromSpeciesAndPersonality(species, personality) == MON_FEMALE;
 }
 
+void TryFormChange(u32 monId, u32 side, u16 method)
+{
+    u32 targetSpecies;
+    struct Pokemon *party = (side == B_SIDE_PLAYER) ? gPlayerParty : gEnemyParty;
+
+    targetSpecies = GetFormChangeTargetSpecies(&party[monId], method, 0);
+    if (targetSpecies != SPECIES_NONE)
+    {
+        TryToSetBattleFormChangeMoves(&party[monId], method);
+        SetMonData(&party[monId], MON_DATA_SPECIES, &targetSpecies);
+        CalculateMonStats(&party[monId]);
+    }
+}
+
 void TryToSetBattleFormChangeMoves(struct Pokemon *mon, u16 method)
 {
     int i, j;
     u16 species = GetMonData(mon, MON_DATA_SPECIES, NULL);
     const struct FormChange *formChanges = gFormChangeTablePointers[species];
 
-    if (formChanges == NULL || (method != FORM_CHANGE_BATTLE_BEGIN && method != FORM_CHANGE_BATTLE_END))
+    if (formChanges == NULL
+        || (method != FORM_CHANGE_BATTLE_BEGIN && method != FORM_CHANGE_BATTLE_END))
         return;
 
     for (i = 0; formChanges[i].method != FORM_CHANGE_END; i++)