Gastly has no true form, due to its body being 95% poisonous gas. However, it consistently appears as a black, spherical Pokémon surrounded by a purple haze. It has a wide, pink mouth with two visible fangs. Though its eyes seem to extend past its round body, visible eyelids surround them. The toxic gas surrounding the main body can induce fainting and suffocation. Gastly lives in old, dilapidated buildings, but it can also be found in caves.