Metal Sonic is an evil robot clone of Sonic The hedgehog. He was created by Eggman to serve him. Metal Sonic appeared in Sonic Cd and other games. But in the events of Sonic Heroes, he later on gained other powers by absorbing a frog and two chaos. Metal Sonic then transformed into Metal Madness and then Metal Overload. Eventually being defeated by Sonic and his friends. There is also a Metal Sonic 3.0 made by Eggman Nega that may or may not have a connection the original. It is confirmed that he will be in Sonic Heroes sequel, Sonic Heroes: Metal Attack, as well.