Zweilous

Jiheddo is the evolution form of Monozu, and the pre-evolution of Sazando. It now has two heads, based off the Greek mythology creature, the Hydra.

Pokemon Black Japanese Pokedex Entry
''Once it eats all the prey in its territory, it moves on to a different area. The two heads don’t get along.''

Pokemon White Japanese Pokedex Entry
''Since the two heads fight so viciously over food, it always eats more than it has to. ''