Mr. 2 Bon Clay is an "okama", a Japanese slang term for someone who is queer. He has a flamboyant attitude, and is prone to singing and dancing. His martial art style is called "Okama Kenpo" in the Japanese manga. Bon Clay ate the Devil Fruit, Mane Mane no Mi (Clone Clone Fruit) which allows him to transform into an exact copy of anyone he has touched. Mr. 2 Bon Clay's swans form the shape of a two. He is defeated by Sanji but is considered a friend by the Straw Hat Pirates, even aiding them in their escape from Alabasta.
Mr. 2 Bon Clay is the only Officer Agent in Baroque Works without a female partner. This stems from the belief that, as an okama, he fills both roles by himself. Likewise, his name is a composite of a male Baroque Works agent's number and a female agent's holiday-based name. "Bon Clay" is celebrated in Japan on either July 15 or August 15 because of the use of a lunar calendar. It is a Buddhist celebration found on the last day of the Bon festival, honoring the dead. Lanterns are lit, and the Bon-Odori is traditionally danced.)
(Source: Wikipedia)