Cubone

From the Pokémon Encyclopedia

Cubone is a Ground-type Pokemon. It can be found in Pokémon Red, Blue, Yellow, Gold, Silver, Crystal, FireRed and LeafGreen. It is mainly found in the Pokémon Tower in Lavender Town. It evolves into Marowak at level 28.

Cubone's real face has never been seen before, thanks to its bone mask.