Mamemon is a ultimate level Digimon who specializes in machine type. The word mame means beans or peas in Japanese, relating to their small, ball like looks. His "boxing gloves" are actually giant and very dangerous and powerful bombs.
A Mamemon inhabits Dark N Area. A "scared" Mamemon on Sayo's farm will submit a request for Machine Species Quest 06: KChessmon's Memory, in which she is asked to recover KnightChessmon (White)'s memories from Thriller Ruins.