The Roboticizer is what Dr. Robotnik uses to enslave his prisoners by transforming them into robots, stripping them of their free will and putting them to work in his factories. But the Roboticizer wasn't originally intended to be used for evil. Ten years ago, Sir Charles Hedgehog invented it to heal injuries and help the elderly live forever, but at some point, Robotnik sabotaged it. Later, after he took over Mobotropolis, he started to roboticized 85% of the populace. Sir Charles and Muttski were his first two subjects. When you are roboticized, you can never be changed back. According to Sir Charles, anyone who is roboticized can still be aware of what's happening, but can't do anything about it. Rotor built a Deroboticizer to change all of Robotnik's victims back to normal. It hasn't been perfected yet.