Key Bum
ItemAfterbirthLocked
familiarGame ID 388★★★★
How do you unlock Key Bum?
In The Binding of Isaac, Key Bum is unlocked by earning the Ultra Greed completion mark as Lazarus (Character).
Structured pathSource-backed requirements are mapped into trackable steps.
Spawns a familiar that follows Isaac and collects Keys for himself, giving random Chests in return.
What unlocking Key Bum leads to
Nothing depends on this yet.
Source: bindingofisaacrebirth.wiki.gg
Imported 2026-09-13