Cyborg Sonic

Cyborg Sonic is one of the countless alternate versions of Sonic the Hedgehog from another dimension. On his Mobius, Dr. Robotnik attempted to defeat the Knothole Freedom Fighters by turning them into cyborgs. However, the enhanced abilities granted them by this transformation allowed them to march on Robotropolis for a final confrontation with him. Sadly, Robotnik turned the tables by completely roboticizing himself. With his teammates killed or otherwise neutralized by this menace, Cyborg Sonic fled onto the Cosmic Interstate looking for help to stop Robotnik. He arrived on Mobius Prime, and when Sonic Prime realized the threat that Robo-Robotnik posed to the many dimensions, he gathered an army of fellow alternate Sonics to combat the foe. Cyborg Sonic joined the final battle, helping to defeat the Giant Borg and fragment both him and the Robo-Robotnik, whose head he took as he departed for his own Mobius. (StH: #19)

Unknown to any of the Sonics, Robo-Robotnik's memory survived and returned to their zone, only for the memory to be stranded aboard an incomplete space station. A chance encounter with the original Robotnik allowed Robo-Robotnik to retrieve the fragment from that dimension and return, eradicating all resistance, including Cyborg Sonic.