Gastly

Gas Pokémon ^#92

Born from gases, anyone would faint if engulfed by its gaseous body, which contains poison.

With its gas-like body, it can sneak into any place it desires. However, it can be blown away by wind.

- Levitate
  This Pokémon is immune to ground-type moves, spikes, toxic spikes, and arena trap. This ability is disabled during gravity or ingrain, or while holding an iron ball. This ability is not disabled during roost.

Said to appear in decrepit, deserted buildings.
It has no real shape, as it appears to be
made of a gas.