diff --git a/include/constants/pokemon.h b/include/constants/pokemon.h
index 85bca6615e..9572745175 100644
--- a/include/constants/pokemon.h
+++ b/include/constants/pokemon.h
@@ -313,6 +313,7 @@
 // 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