Guppy's Hairball
Next upBecome Guppy.
In one run, pick up 3 items or trinkets from the Guppy set (for example Guppy's Head, Guppy's Paw or Dead Cat). Isaac turns into Guppy.
The wiki's Guppy page lists the full set.
Sources:AchievementsGuppy
Achievement
Become Guppy.
In-game: “Unlocked a new item.”
Sources:AchievementsGuppy
Become Guppy.
In one run, pick up 3 items or trinkets from the Guppy set (for example Guppy's Head, Guppy's Paw or Dead Cat). Isaac turns into Guppy.
The wiki's Guppy page lists the full set.
Sources:AchievementsGuppy