Boom Fly

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.0
Found In

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

Variants

Red Boom Fly

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.1
Found In	Chance to replace Boom Flies

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

Drowned Boom Fly

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.2
Found In	Chance to replace Boom Flies and Red Boom Flies in the Flooded Caves

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

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.3.0
Found In

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

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.3.1
Found In

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

Bone Fly

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.4
Found In

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

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.5
Found In

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

Base HP	20
Base HP	20
Stage HP	0
Stage HP	0
Entity ID	25.6
Found In	Found on the Ascent to Home.

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.

Although they cannot be killed normally before their self-destruct sequence finishes, status effect damage such as poison is capable of killing them.

They are exclusive to the Ascent to Home.

Gallery

• 

  A Dragon Fly's appearance in Ashpit.

• 

  A Dragon Fly X's appearance in Ashpit.

• 

  Concept art for what appears to be the Bone Fly alongside concept art for Pin, Mega Maw, and The Gate.