Level 2 Fly

The Level 2 Fly is an enemy that moves towards Isaac somewhat erratically, dealing contact damage.

Full Fly
The Full Fly behaves similarly to the Level 2 Fly and Red Boom Fly combined: it chases Isaac and shoots 6 blood shots in all directions upon death. Full Flies do not actively run into Isaac, but will orbit around him closely until he moves, which may end up causing him to run into the fly.

Level 2 Willo
Level 2 Willos are stronger versions of the Willo that orbit enemies rather than Isaac; however, when there are no enemies left, they will chase Isaac and, upon catching up, attempt to orbit in a tight ring around him and maintain that distance from him while shooting at him, just like their weaker counterparts.