Boom Fly

Boom Flies roam around the room diagonally, dealing contact damage and exploding with a large blast radius upon death. slows them down, but they remain dangerous.

Red Boom Fly
Red Boom Flies roam around the room diagonally, dealing contact damage and releasing 6 blood shots in all directions upon death. will only slow down their movement.

Drowned Boom Fly
Drowned Boom Flies fly around the room diagonally, dealing contact damage. Upon death, they explode and release 4 blood shots in the cardinal directions, occasionally spawning a Drowned Charger.

If a Drowned Boom Fly dies while over an obstacle or pit, the Drowned Charger will not be spawned.

Dragon Fly
Dragon Flies fly around the room diagonally, dealing contact damage. Upon death, they spawn 4 lines of fire in the cardinal directions.

Dragon Fly X
Dragon Fly X is identical to the Dragon Fly in behavior, but upon death, it spawns 4 lines of fire in the diagonal directions.

Bone Fly
Bone Flies fly around the room diagonally, dealing contact damage and firing bones at Isaac when they are lined up, similar to a Bony. Upon death, they shoot 3 evenly spaced bones (one of them aligned towards the closest cardinal direction to Isaac).

Sick Boom Fly
 Sick Boom Flies  fly around the room diagonally, dealing contact damage and trailing poisonous gas. Upon death, they explode into eight clouds of gas and release 6 green shots in all directions. The poison gas left behind upon death persists for much longer, but will dissipate when the room is cleared.

Tainted Boom Fly
Tainted Boom Flies are bigger and stronger versions of Boom Flies. They fly around the room diagonally, dealing contact damage. When near death, they will start to emit a cross-shaped glow; if they are not killed soon after, they will self-destruct and send explosions in a cross-shaped marker across the room.

They are exclusive to the Ascent to.