Binding of Isaac: Rebirth Wiki
Binding of Isaac: Rebirth Wiki

Added in Afterbirth

GB Bug is an unlockable passive item added in The Binding of Isaac: Afterbirth.


  • Removed in Repentance Spawns a familiar that bounces diagonally around the room, deals 8 damage per tick or 120 damage per second and applies a random status effect to enemies it comes in contact with. The familiar also has a chance to re-roll pickups that it passes over into other pickups, chests, or items, in an uncleared room only (with at least one enemy alive).
  • Added in Repentance Spawns a familiar that follows Isaac. Double tapping the fire button launches it forward, causing it to reroll the first monster, trinket, or pickup it hits. It respawns after clearing a room.
    • If it cannot reroll an enemy (e.g. a boss), it will deal 8 damage instead.
    • It can also be used to reroll trinkets into pickups.
    • Pickups may also be rerolled into chests.


  • Removed in Repentance GB Bug can block projectiles.
  • Removed in Repentance GB Bug does more damage per second than 15►The Peeper The Peeper, with the added random status chance.
  • Added in Repentance GB Bug is able to reroll Throwable Bombs into normal consumables. After doing so, the corresponding Bomb Grimace will generate another Throwable Bomb, making it able to generate a potentially large amount of free consumables.
  • Added in RepentanceThe Twins The Twins: the familiar can be duplicated even if it hasn’t respawned; by constantly moving to new rooms, GB Bug can constantly respawn, allowing pickups to be rerolled indefinitely.

In-game Footage[]

In Rebirth Removed in Repentance[]

In Repentance Added in Repentance[]


  • Before Repentance, GB Bug's pickup quote was "Game breaking bug, right away!"
  • This item's in-game appearance may be a reference to "Missingno.", a famous bug occurring in the first Pokémon games.
  • As Edmund confirmed on Twitter the pickup quote "Game breaking bug, right away!" is a reference to a quote by Phil Fish in Indie Game: The Movie, where he says the same words when a bug is discovered in the game "FEZ" on the first day it is being shown at PAX.


PC Removed in Afterbirth † Hard mode only 9B7E 3G67 (Treasure Room adjacent to spawn, curse of the labyrinth)

PC Removed in Afterbirth † Normal mode only GZWT H4LE (First floor Treasure Room)

PC Removed in Repentance Normal and hard modes only 44W2 XHJ8 (Treasure Room adjacent to spawn)

PC Added in Repentance Normal and hard modes only OCML SLQN (First floor Treasure Room)

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