Guppy is a transformation in The Binding of Isaac.
Obtained by acquiring any 3 items with the guppy tag.
Grants Isaac flight and spawns a Blue Fly 66% of the time when a tear hits an enemy.
This page shows the latest information as of the new Repentance+ (Online Co-op) DLC.
To see information about this transformation for the previous Repentance version, check this page instead.