Fly Bomb

Fly Bombs are enemies added in The Binding of Isaac: Repentance. They are characterized by their appearance of a small Bomb with wings.

They chase Isaac, attempting to circle around him as they do so. Upon death, they turn into a tiny Bomb that explodes shorty after. Running into a Fly Bomb causes it to explode instantly.

Eternal Fly Bomb
Eternal Fly Bombs are enemies and variants to the original Fly Bombs added in The Binding of Isaac: Repentance.

They spawn in a group of 3 and orbit Boom Flies spawned by The Horny Boys. Similar to Eternal Flies, they are immune to all damage until their respective Boom Fly dies. Then, they turn into tiny Bombs that explode shortly after. While generally immune to damage they can still be ran into and will explode like regular Fly Bombs.