Uma Uma no Mi

The Uma Uma no Mi is a Zoan-type Devil Fruit that allows its user to transform into a horse hybrid and a full horse at will. "Uma" is Japanese for "horse". In the Viz Manga and FUNimation dub, it is called the Horse-Horse Fruit. It was eaten by Gan Fall's bird, Pierre.

Strengths and Weaknesses
This fruit allows the eater to transform into a horse or horse hybrid at will.

This fruit doesn't seem to have any specific weaknesses, aside the standard Devil Fruit weaknesses.

Usage
The main usage of the Devil Fruit is merely allowing Gan Fall to claim that he rides a Pegasus, when in reality Pierre's original bird form is more than big enough to transport him wherever he goes. However, as a horse, Pierre can also bite anyone who disrespects his master, something he cannot do as a bird.