As part of its ongoing efforts to promote every single Pokémon out there, The Pokémon Company has shared special content dedicated to Golbat:
Did you know? Every once in a while, you’ll see a Golbat that’s missing some fangs. This happens when hunger drives it to try biting a Steel-type Pokémon. They can suck down over 10 ounces of blood in one go. They have been known to drink so much blood that they can no longer fly.
Source: @Pokemon
