Hamburg is a huge gorilla-like human who is almost always seen laughing. He often carries Foxy around and tends to help him cheat. Although he seems to respect and admire Foxy, he never fails to laugh cheerfully when he fails. Hamburg is also the leader of the "Groggy Monsters", despite being the smallest, and during the Groggy Ring is defeated by a series of kicks from Sanji. However, in the filler, he returns to compete in other games.
Like the other Groggy Monsters who are named after culinary names, Hamburg is named after the Japanese culinary dish known as Hamburg.
(Source: One Piece Wikia)