Binding of Isaac: Rebirth Wiki

Smart Fly is a passive item.


  • Spawns a fly familiar whose behavior changes depending on whether or not Isaac has taken damage in the current room.
    • The fly always deals 1.5 damage per tick or 22.5 damage per second on contact with enemies.
    • Before Isaac takes damage, the fly serves as an orbital, blocking enemy shots.
    • After Isaac takes damage, this fly will seek out nearby enemies and attack them.
  • This item belongs to the Beelzebub set. Collecting three items from this set will transform Isaac into a giant humanoid fly.


  • Smart Fly does not take up one of the three orbital slots; it floats between two of the other orbitals.
  • While behaving like an orbital, Smart Fly will break away from Isaac if he is traveling fast enough and will follow Isaac until he slows down enough to reattach. This is the only orbital item in the game that exhibits such behavior.


  • Added in Afterbirth †Duct Tape Duct Tape: Fly will stay in place when orbiting Isaac but will still pursue enemies.

In-game Footage[]


PC CAKK GWMX (First floor treasure room)

PC YYH2 YJ4B (Treasure room adjacent to spawn)

PC ER9T 2RPF (First floor treasure room)

PS4 WV2E FB1R (First floor treasure room)

PS4 1ZTZ EC7A (First floor treasure room)

Switch Greed mode only 396D QBP0 (First Golden Treasure Room)