Binding of Isaac: Rebirth Wiki

After picking up 3 items from the following list Isaac turns into his cat Guppy. As Guppy, Isaac gains flight, and when one of his tears or one of Removed in Repentance his familiar's tears hit an enemy, a Blue Fly spawns. Also applies to laser-like attacks, such as Brimstone Brimstone or Technology Technology.

  • Added in Repentance The chance to spawn a fly is 50%.

Activated Collectibles[]

Name ID Icon Quote Description Added in Repentance Quality
Guppy's Head 5.100.145
Guppy's Head
1 rooms
Reusable fly hive Spawns 2-4 friendly Blue Flies that damage enemies. 3
Guppy's Paw 5.100.133
Guppy's Paw
Soul converter Upon use, converts one Red Heart Container into three Soul Heart Soul Hearts. 3

Passive Collectibles[]

Name ID Icon Quote Description Added in Repentance Quality
Dead Cat 5.100.81 Dead Cat 9 lives Sets Isaac's Red Heart Containers to 1, but grants 9 extra lives. After dying, Isaac respawns with 1 Red Heart Container. 3
Guppy's Collar 5.100.212 Guppy's Collar Eternal life? Grants a permanent 50% chance to respawn with 1/2 of a Red Heart after death. 2
Guppy's Hair Ball 5.100.187 Guppy's Hair Ball Swing it Spawns a familiar that loosely follows behind Isaac, which blocks shots can be swung like a flail to damage enemies. Grows bigger by killing enemies. 1
Guppy's Tail 5.100.134 Guppy's Tail Cursed? Room Clear Awards have a 1/3 chance of being replaced with a Chest and a 1/3 chance being replaced with nothing. 2
Added in Repentance Guppy's Eye 5.100.665 Guppy's Eye An eye for secrets Shows the contents of Chest Chests, Fire Place Fire Places, Added in Afterbirth Grab Bag Sacks, and Shopkeeper Shopkeepers before they're opened/destroyed. 2


Name ID Icon Quote Description
Added in Repentance Kid's Drawing 5.350.169 Kid's Drawing Looks familiar... While held, counts towards Guppy Guppy.


  • Technology 2 Technology 2 spawns flies only very rarely
  • Added in Repentance If all the 9 extra lives have been consumed, Dead Cat Dead Cat is removed from Isaac's inventory. This causes the transformation to be removed.
  • Added in Repentance Duplicated Guppy items count towards the transformation.

Unlockable Achievements[]


  • This transformation is a reference to Edmund's first cat, as seen in some of his early videos on his personal channel.[1]
  • In the original Binding of Isaac, this transformation was called "Cursed?"
  • Added in Afterbirth † Transforming into Guppy as The Forgotten The Forgotten will give him the appearance of a cat's skeleton.
  • Added in Repentance The guppy item tag determines if an item counts towards the transformation, except for Kid's Drawing Kid's Drawing which seems to be hard-coded to count as a Guppy item despite not having the tag.


PC Normal mode only XWN6 1YWH (The Basement I - Curse Room above spawn contains 2 Red Chests and Bomb Chest, Guppy's Collar, Guppy's Head and Dead Cat respectively)

PC Hard mode only JJZE PR1R (Cellar XL - Curse Room contains Guppy's Tail, Devil Deal red chests contain Dead Cat and Guppy's Collar)

PC Normal mode only 7TC3 43F1 (The Cellar I - Curse Room above spawn contains 2 Red Chests and Bomb Chest, Guppy's Collar, Guppy's Paw and Guppy's Head respectively

PC Added in Afterbirth Greed mode only W82M ZL3F (The Basement, Eden only - Start with Guppy's Head, Golden Treasure Room contains Guppy's Paw, Silver Treasure Room contains Guppy's Tail)

3DS Hard mode only F4GJ 7ZHK (The Caves II, Boss Challenge Room, three Red Chests with Guppy's Tail, Guppy's Head and Guppy's Paw) PCHard mode only4RF6 7SZK (The Basement, from the starting room: on the left two items in red chests, on the right after clearing it inside the red chest there's the third item. Only works with Cain.)