Binding of Isaac: Rebirth Wiki

(except in Rebirth)

Key Bum is an unlockable passive item added in The Binding of Isaac: Afterbirth.

Effects[ | ]

  • Spawns a familiar that follows Isaac around and collects KeyKeys, dropping random ChestChests in return.
  • This item belongs to the Super BumSuper Bum set. Collecting three items from this set will transform Isaac's bums into Super Bum.

Notes[ | ]

  • Key Bum will not pick up Golden KeyGolden Keys.
  • (in Afterbirth †) Key Bum will pick up Charged KeyCharged Key without additional benefit.
  • (except in Repentance) From a scoring perspective, Keys that Key Bum picks up count towards your Schwag bonus on daily runs.
  • Key Bum does not join the line of familiars that follow behind Isaac.

Synergies[ | ]

  • Collectible BFFS! iconBFFS!: Familiar is bigger and drops chests more often.
  • Flat PennyFlat Penny: Chests frequently contain pennies, which have a chance of spawning more keys for Key Bum to pick up, possibly lead to a loop.
  • (in Repentance)Gilded KeyGilded Key / The Left HandThe Left Hand: Works as expected.
  • (in Repentance)Collectible Guppy's Eye iconGuppy's Eye: Allows Isaac to choose which Locked Chests are worth opening and which to pass, thus saving keys. Great for min-maxing.

In-game Footage[ | ]

Trivia[ | ]

Bugs[ | ]

Bug Bug! If Credit CardCredit Card is used in a ShopShop with Keys, Key Bum will not be able to pick up the free keys. This can be fixed if Isaac leaves and re-enters the shop.
Bug Bug! (in Afterbirth †) Charged KeyCharged Keys do not increment Key Bum's key count when picked up.