They can be naturally found in floors such as the Catacombs from the original game, and can replace Pooters where ever they spawn. In Rebirth, they also can appear in The Caves, The Depths, and Necropolis.
BehaviorThey behave identically to regular Pooters, but shoot 2 projectiles in a V-pattern similar to that of the Keeper.
If a Fat Fly is near a pile of poop for long enough, it can transform into a Pooter just like a Fly.
Although Fat Flies' projectiles can easily be avoided by going in between them, dodging multiple attacks from them can prove difficult as they often appear in groups.
Only available for the original game. They fire 3 sets of 3 shots (one in the center and two in a V-formation).