Guppy

Isaac turns into his cat Guppy after picking up any 3 distinct items from this item pool. As Guppy, Isaac gains flight.

When Isaac or one of his familiars hits an enemy with a tear, a Blue Fly spawns.

Blue Flies have a 50% chance to spawn when Isaac or one of his familiars hits an enemy with a tear.

Laser attacks from, , and   also work normally, but  and  spawn flies only very rarely. Explosions and non-tear based attacks from familiars do not spawn flies.

Trivia

 * This transformation is a reference to Edmund's first cat, as seen in some of his early videos on his personal channel.
 * In the original Binding of Isaac, this transformation was called "Cursed?"
 * Transforming into Guppy as The Forgotten will give him apperance of a cat's skeleton.

Seeds
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) JJZE PR1R (Cellar XL - Curse Room contains Guppy's Tail, Devil Deal red chests contain Dead Cat and Guppy's Collar) 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  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)  F4GJ 7ZHK (The Caves II, Boss Challenge Room, three Red Chests with Guppy's Tail, Guppy's Head and Guppy's Paw)