- For other uses, see Fly (disambiguation).
Black Flies are very common enemies, found in almost all floors. They can first naturally spawn in The Basement, and also come in sort of multiple variants.
Black flies buzz around the room randomly, often moving away from the player. They cannot damage Isaac at all, even by touch, making them completely harmless. However, they can turn into relatively dangerous Pooters if they fly around Poop for too long.
- During the credits, the Black Fly, Psychic Maw, and Embryo's images are the only monsters that are animated.
- Black Flies, along with other type of flies, are one of the enemies with lack of champion variants.
- Same apply to Spiders and few other monsters.