Mecha Sonic (Sonic the Comic)

Silver Sonic is an early robotic copy of Sonic the Hedgehog, which defended Robotnik's Death Egg. It is about twice as tall as Sonic, coloured a uniform metallic grey, and gets its speed from jet boosters on its back and on the heels of its feet. Sonic considered it a pathetic imitation.

History
Sonic encountered Silver Sonic on his first trip to the Death Egg (as recorded in Sonic the Hedgehog 2) and believed that he had trashed the robot. However, although the Death Egg had been heavily damaged and rendered useless to Robotnik, it was still in orbit around Mobius. Some time later its orbit began to degrade, and was set to crash into the Emerald Hill Zone. Sonic and Tails returned to the Death Egg, where they found Silver Sonic damaged but operational. It told them that intruders may not pass, by order of "the omnipotent Doctor Robotnik".

Sonic fought the robot again, hitting it with a Spin Attack on its head, then avoiding a charge, before finally kicking its head off and destroying it for good.

Trivia

 * In this continuity, the robot was not referred to by name.
 * In Nigel Kitching's original script for the story in Sonic the Comic #6, it is mentioned that the Silver Sonic actually repaired itself after Sonic's previous encounter with it.