The Koopa Bros. are four differently colored ninja Koopa Troopas. Their leader is Red Ninjakoopa and the other members are the Black, Green, and Yellow Ninjakoopas. They first appeared in Episode 4 and were fought in episodes 4, 5, and 6 before being defeated by Mecha Sonic. The Koopa Bros. are a rather obvious parody of the Teenage Mutant Ninja Turtles. It is presumed that they really are brothers.