GB Bug

Effects

(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.
- Items and opened chests cannot be rerolled.
- Pickups have a 10% chance of becoming chests .
  - If a chest is rerolled, it has a 28% chance of staying as some kind of a chest.

(Removed in Repentance) GB Bug can block projectiles.
(Removed in Repentance) GB Bug does more damage per second than The Peeper, with the added random status chance.
(Added in Repentance) GB Bug is able to reroll (Added in Repentance) (Throwable Bomb) Throwable Bombs into normal consumables. After doing so, the corresponding (Added in Repentance) (Bomb Grimace) Bomb Grimace will generate another Throwable Bomb, making it able to generate a potentially large amount of free consumables.
(Added in Repentance) Rerolled champion enemies will retain their color, unless they reroll into a monster that cannot naturally spawn as a champion.

(Added in Repentance)(The 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.