Ushi Ushi no Mi, Model: Bison

The Ushi Ushi no Mi, Model: Bison (Ushi Ushi Fruit, Model: Bison) is a Zoan type Devil Fruit that allows a person to transform into both a bison-human hybrid and a full bison. ("Ushi" means cow or ox in Japanese.) This fruit is one of many Ushi Ushi Fruit models found in the One Piece world.

In the 4Kids dub, this fruit is simply called the Ox-Ox Fruit, while the Viz Manga calls it the Ox-Ox Fruit, Bison Model.

The Ushi Ushi Fruit was consumed by Dalton of the former Drum Kingdom.

Usage
Fiddle Banff (フィドル突撃(バンフ) Fiddle Assault) - A technique in which Dalton transforms into his bison-human hybrid form and uses his weapon in a fast attack. This was first used on some of Wapol's soldiers.

Translation and Dub Issues
In the 4Kids dub of the anime, the fruit's name was changed to Ox Ox Fruit in order to cater to an english audience. While this is technically correct, due to the lack of any words suggesting otherwise, the name in the 4Kids dub technically implies that Dalton turns into an ox instead of a bison. While the words "ox" and "bison" can sometimes be interchangeable, they usually refer to two different breeds of bovine.