Mimicry

Mimicry is a terrain-dependent ability that dynamically alters the user's typing based on the active terrain condition on the battlefield. When Electric Terrain is active, the Pokémon becomes an Electric-type. Grassy Terrain transforms it into a Grass-type, while Misty Terrain changes it to a Fairy-type. Under Psychic Terrain, the Pokémon adopts Psychic typing. When no terrain is present, the Pokémon retains its original typing.

This ability creates interesting strategic considerations, as the type change affects both offensive STAB calculations and defensive matchups. The transformation is immediate upon terrain activation, whether through moves like Grassy Terrain or abilities like Electric Surge. Notably, Mimicry only changes the user to a single type regardless of their original dual typing, completely overriding their natural type combination while terrain persists.

Galarian Stunfisk is currently the sole possessor of this ability, and its Ground/Steel typing becomes particularly relevant in terrain-heavy metagames. The ability can catch opponents off-guard, suddenly granting Stunfisk unexpected resistances or weaknesses. However, the reliance on terrain control limits its consistency, as opponents can potentially manipulate or remove terrain to force unfavorable type matchups. This makes Mimicry most effective on teams built around terrain synergy, where the type changes align with broader strategic goals.