Iron Sonic? Can’t find character or name

I know about Metal Sonic; it’s not who I’m talking about.

I remember in the first 2D games seeing another Sonic-like enemy with a metallic appearance, coloured grey. Unlike Metal Sonic, that character really looked like Sonic, shape-wise (big head and all).

I periodically search for it and sometimes I even find it in an old blurry screenshot, but never seem to retain its name. Any help in finding out who it is?