Who is Sonic's evil twin?

I'm curious, who exactly is the nefarious counterpart of the beloved blue hedgehog, Sonic? Is there a sinister doppelganger lurking in the shadows, plotting against the hero of the Sonic universe? If so, what makes this evil twin so dangerous, and what sets them apart from the speedy hero we all know and love? I'm eager to learn more about this mysterious figure and their role in the Sonic universe.