Thread:GazzaB9/@comment-24839525-20181008173226/@comment-30134917-20181009143104

There's a few but his main three are Neo Metal Sonic, Metal Madness, and Metal Overlord. There are also two lesser known ones called Titan Metal Sonicand Giga Metal. I probably forgot a few but those are the ones that first appear when you search "Metal Sonic transformation".