As part of its ongoing efforts to promote every single Pokémon out there, The Pokémon Company has shared special content dedicated to Gastly:
Did you know? 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.
Source: The Pokémon Company
Source: Pokemon
