Add Meteorite form change functionality

src/data/items.h

@@ -9048,8 +9048,8 @@ const struct Item gItems[] =
         .description = sMeteoriteDesc,
         .importance = 1,
         .pocket = POCKET_KEY_ITEMS,
-        .type = ITEM_USE_BAG_MENU,
-        .fieldUseFunc = ItemUseOutOfBattle_CannotUse,
+        .type = ITEM_USE_PARTY_MENU,
+        .fieldUseFunc = ItemUseOutOfBattle_FormChange,
     },
 
     [ITEM_MAGMA_EMBLEM] =

src/data/pokemon/form_change_tables.h

@@ -385,6 +385,28 @@ static const struct FormChange sRayquazaFormChangeTable[] = {
 };
 #endif //P_FAMILY_RAYQUAZA
 
+#if P_FAMILY_DEOXYS
+static const struct FormChange sDeoxysNormalFormChangeTable[] = {
+    {FORM_CHANGE_ITEM_USE, SPECIES_DEOXYS_ATTACK,  ITEM_METEORITE},
+    {FORM_CHANGE_TERMINATOR},
+};
+
+static const struct FormChange sDeoxysAttackFormChangeTable[] = {
+    {FORM_CHANGE_ITEM_USE, SPECIES_DEOXYS_DEFENSE,  ITEM_METEORITE},
+    {FORM_CHANGE_TERMINATOR},
+};
+
+static const struct FormChange sDeoxysDefenseFormChangeTable[] = {
+    {FORM_CHANGE_ITEM_USE, SPECIES_DEOXYS_SPEED,  ITEM_METEORITE},
+    {FORM_CHANGE_TERMINATOR},
+};
+
+static const struct FormChange sDeoxysSpeedFormChangeTable[] = {
+    {FORM_CHANGE_ITEM_USE, SPECIES_DEOXYS_NORMAL,  ITEM_METEORITE},
+    {FORM_CHANGE_TERMINATOR},
+};
+#endif //P_FAMILY_DEOXYS
+
 #if P_FAMILY_BURMY
 static const struct FormChange sBurmyFormChangeTable[] = {
     {FORM_CHANGE_END_BATTLE_TERRAIN, SPECIES_BURMY_PLANT_CLOAK, BATTLE_TERRAIN_GRASS},

src/data/pokemon/species_info/gen_3.h

@@ -8176,6 +8176,7 @@ const struct SpeciesInfo gSpeciesInfoGen3[] =
         PALETTES(DeoxysNormal),
         ICON(DeoxysNormal, 0),
         LEARNSETS(DeoxysNormal),
+        .formChangeTable = sDeoxysNormalFormChangeTable,
     },
 
     [SPECIES_DEOXYS_ATTACK] =
@@ -8199,6 +8200,7 @@ const struct SpeciesInfo gSpeciesInfoGen3[] =
         PALETTES(DeoxysAttack),
         ICON(DeoxysAttack, 0),
         LEARNSETS(DeoxysAttack),
+        .formChangeTable = sDeoxysAttackFormChangeTable,
     },
 
     [SPECIES_DEOXYS_DEFENSE] =
@@ -8222,6 +8224,7 @@ const struct SpeciesInfo gSpeciesInfoGen3[] =
         PALETTES(DeoxysDefense),
         ICON(DeoxysDefense, 0),
         LEARNSETS(DeoxysDefense),
+        .formChangeTable = sDeoxysDefenseFormChangeTable,
     },
 
     [SPECIES_DEOXYS_SPEED] =
@@ -8245,6 +8248,7 @@ const struct SpeciesInfo gSpeciesInfoGen3[] =
         PALETTES(DeoxysSpeed),
         ICON(DeoxysSpeed, 0),
         LEARNSETS(DeoxysSpeed),
+        .formChangeTable = sDeoxysSpeedFormChangeTable,
     },
 #endif //P_FAMILY_DEOXYS