Guppy

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 his familiar's tears hit an enemy, a Blue Fly spawns. Also applies to laser-like attacks, such as Brimstone or Technology.

The chance to spawn a fly is 50%.

Activated Collectibles[]

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

Passive Collectibles[]

Name	ID	Quote	Description	Quality
Dead Cat	5.100.81	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	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	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	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
Guppy's Eye	5.100.665	An eye for secrets	Shows the contents of Chests, Fire Places, Sacks, and Shopkeepers before they're opened/destroyed.	2

Trinkets[]

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

Notes[]

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

Unlockable Achievements[]

Guppy's Hairball - Become Guppy.

Cat Got Your Tongue - Become Guppy.

Trivia[]

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?"
Transforming into Guppy as The Forgotten will give him the appearance of a cat's skeleton.
The guppy item tag determines if an item counts towards the transformation, except for Kid's Drawing which seems to be hard-coded to count as a Guppy item despite not having the tag.

Seeds[]

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

PC 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 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 F4GJ 7ZHK (The Caves II, Boss Challenge Room, three Red Chests with Guppy's Tail, Guppy's Head and Guppy's Paw) PC4RF6 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.)