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Guppy is Isaac's Pet cat, and mentioned as sole heir of Isaac's findings in his last will.

Guppy has a total of five items related to it in the game. Four of them are Devil Room items and can transform Isaac into his cat, which will unlock the fifth item.

Except for Dead Cat, all of these items are exclusive to Wrath of the Lamb.

Transforming into Guppy


Isaac after transforming.

Dead Cat, Guppy's Tail, Guppy's Head or Guppy's Paw have a unique feature: Isaac can permanently transform himself into Guppy when he collects any three of them in a single playthrough.

Once transformed, Isaac will gain flight and The Mulligan (which spawns blue flies while attacking).

Transforming for the first time unlocks Guppy's Hairball.


  • Having picked the items up at some point is the only thing that matters (so it is visible in the section of your items collection that you see when you pause the game)
    • Although Guppy's Head and Paw are both activated items, Isaac will still transform even if he picked up one of them in an earlier floor and left it behind, or rerolled it with the D6.
      • Therefore the latter can be a handy method to acquire another Guppy item (for instance if you already had an activated item and picked up Guppy's Paw in the Devil Room, you can use it, switch back to your old item, reroll the paw and get another Devil Room item out of it.)
  • If the third Guppy item you pick up is an activated item the game may bug, so you might have to switch out the final active item before becoming Guppy.
  • The Left Hand trinket can help a lot to turn into Guppy, since it turns all future chests into red chests, which highly increases the chance of getting Guppy-items. Combined with Guppy's Tail early on, this almost ensures becoming Guppy for the playthrough.

Related items

Dead Cat (Guppy)

File:Dead Cat.png

Your HP is set to 1. You are followed by a floating cat head and have 9 lives (these still count as deaths on the statistics screen).

You can increase your max HP as normal, but after each death it will reset to 1 again. (1 soul heart with ???)

Even if you have more than three heart containers, you will only have one heart container left once you purchase Dead Cat, since it sets your HP to 1 immediately, not after your first death.

If you buy him for the price of 2 hearts from the devil and you have 2 or fewer hearts, you will acquire him, die, and respawn with 1 heart (therefore losing 1 of the extra lives).

It is possible to purchase other Devil Room items without having enough hearts with this item.

Bug/Exploit: After defeating a boss, if you die after the item appears you will be able to fight the boss a second time for yet another item. (Pick up the item, then kill yourself with a bomb or something similar.)

You will then respawn outside the boss room with one less life on your counter. Going back inside the boss room allows you to now fight the boss again for another item.

Can be done as long as you have additional lives on your counter. (Can also be performed after picking up a 1UP.)

Guppy will sometimes appear as a collectible item as well as in the Devil room. Collecting more than one Guppy will not add any more lives if the player already has 9, but will reset your health back to 1.

Guppy's tail

File:Guppystail icon.png

Guppy's Tail is another devil room item that costs one heart; alternatively it can be found in red chests or very rarely as a boss drop. Once collected, chests spawn with increased frequency upon clearing a room and higher chance to be golden chests. Highly effective if you have an excess of keys.

Guppy's head

Guppys Head Icon

Spawns 2-4 Blue Flies to damage enemies. Flies won't spawn if entering a door while using it. Found in Devil Room for 2 hearts, the Curse Room, Challenge Room, or as a drop from The Fallen.

Recharges after each room.

Guppy's paw

File:Guppys paw.png

Note: Soul hearts are not to be mistaken with eternal (white) hearts, soul hearts are the temporary steel ones. I learned this the hard way...

Turns one Heart Container into 3 Soul Hearts. This item does nothing for ??? and is found in Curse Rooms, Devil Rooms and from bosses. Can be used indefinitely provided there is at least one heart container left.

It is possible to get 3 extra Soul Hearts if you are already at zero Heart Containers and you use a Strength Card or you get the All Stats Up from Liberty Cap, which will give you 3 Soul Hearts upon use, yet when the effects wear off, the game considers your character to have -1 Heart Container, meaning the next HP UP you will get won't provide you a Heart Container, but a Soul Heart instead - as when playing with ???. You can evade this drawback however by using another Strength card or by reentering rooms until Liberty Cap's All Stats Up effect takes place. In this case, you will get a permanent Soul Heart, and the game will consider your Heart Containers to be at 0 again afterwards. (So the next HP UP will give you a permanent heart container again.)

Guppy's Hairball


Note: This item does not count as a Guppy item towards transformation.

A unique type of familiar that loosely follows behind Isaac. Can be swung like a flail by rapidly spinning Isaac in a circle.

Deals damage when it collides with enemy units. If an enemy unit is killed by the ball, it increases in size up to a maximum limit. The larger the ball becomes the easier it is to swing, the larger its collision circle becomes, and the higher its damage becomes. Size is reduced at the start of each floor.

Unlike other Guppy collectibles it isn't found in Devil Rooms, but in Treasure Rooms.

Unlocked by transforming your character into Guppy. Achieved by collecting 3 Guppy items in one playthrough (any combination of Guppy's Tail, Dead Cat, Guppy's Head, and Guppy's Paw).


  • It can be assumed that Guppy is dead by the time Isaac explores the world under the trapdoor, since you can find pieces of him throughout the adventure. Eventually you can also find the item Dead Cat which represents Guppy himself.
  • Guppy is actually a reference to Edmund McMillen's own pet called Guppy
  • Guppy's Paw is a reference to The Monkey's Paw by W.W. Jacobs
  • Completing the Cathedral with Guppy won't count as a Character when unlocking the Polaroid if you beat the Cathedral with a character you already played with.
  • If you get a duplicate of the same Guppy item (For example, 2 Guppy's Tails), it will treated as a third item.
    Double tail
    This does not work with two Dead Cats (+ Guppy's Tail)

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