Here's a commission I did of a dude turning into Sonic, then Sonic into Mecha Sonic, from Archie comics issue 39, and the Mecha Madness special.

So, purple highlights on the hair. Cuz it looked better than blue, and blue was kinda a bit too over the top for me anyway. Like, bashing you over the head THIS GUY'S GONNA TURN INTO SONIC. Well, anymore than the power ring on a plaque thing.

THE POWER RING ON A PLAQUE THING! Which starts this whole crazy sequence. At the end of the issue where Sonic's collected his billionth ring, and the Ancient Walkers take him on this weird spirit quest thing (as spirit quests are often weird), Sonic mounts the ring on a plaque, with the inscription "Over One Billion Served". Since that's how he gets his will and true form back after being roboticized, it seemed like a good place to start. The "Brain-Burn-Thru" system was something designed to destroy any trace of will or spirit in a roboticized person--the protective aura from attaining his billionth ring helped preserve, and then call back Sonic's will. AND THAT'S WHY IT'S IN THIS SEQUENCE.