Binding of Isaac: Rebirth Wiki

(except in Rebirth)

Lost Fly is a passive item added in The Binding of Isaac: Afterbirth.

Effects[ | ]

  • Spawns a fly familiar that moves in a straight line and attaches itself to the first wall or obstacle it comes into contact within each room.
    • The Lost Fly will then move around the room functionally similar to the GutsGuts.
  • (except in Repentance) If any enemies walk into its path, it will deal 7 contact damage per tick or 105 damage per second.
  • (in Repentance) Lost Fly deals 7 contact damage every 7 ticks, or 30 damage per second. Enemies near Lost Fly will target it instead of Isaac.
    • Some enemies that do not normally give chase to Isaac, such as MulliganMulligans, will chase after the Lost Fly if nearby it.
  • If the obstacle it is attached to is destroyed then it will continue rolling in the direction it was previously traveling until it meets another wall or obstacle.
  • This item belongs to the BeelzebubBeelzebub set. Collecting three items from this set will transform Isaac into a giant humanoid fly.

In-game Footage[ | ]

Trivia[ | ]

  • (in Repentance) The fly will glow slightly in Curse of DarknessCurse of Darkness making its position always visible.
  • The name of the item is likely a reference to the maze-solving algorithm called the left-hand rule, which is based on walking forward and turning left as far as possible until you find an exit to the maze.