GB Bug

How do you unlock GB Bug?

In The Binding of Isaac, GB Bug is unlocked by earning the Ultra Greed completion mark as Eden (Character).

[Before Repentance] Spawns a familiar that bounces diagonally around the room, applying a random status effect to enemies it hits and has a chance to re-roll pickups it passes over. / [Repentance] Spawns a familiar that follows Isaac. Double tapping the fire button launches it forward, causing it to reroll the first monster or pickup it hits.