kuromaru (mugen)

Infamous M.U.G.E.N hentai character. It is a dark-skinned giant eyeball that can transform into various objects or creatures to rape defeated opponents.

After Kuromaru was released, some character creators started turning M.U.G.E.N into a hentai fighting game by making a dozens of hentai characters, or converting other characters to be compatible with hentai moves.