The Pokémon Company itself questions how Gastly is able to kick a ball without legs

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