Knuckles' robotic doppelgänger first appeared in Sonic R
Archie Sonic #243 kicks off the "Endangered Specias" arc, with a focus on the thinning echidna population. The Death Egg Mk II has brought fiery death upon the home of Knuckles' people, but before Sonic and crew can save the day, Metal Knuckles busts in and wrecks their sh*t.
Metal Knuckles first appeared in the racing game Sonic R for the Saturn. Like the creepy Tails Doll from the same game, it's bound to be a major adversary in these latest issues. Good. Nice to see the heroes sweat a bit.
Sonic the Hedgehog #243 arrives tomorrow in comic stores. You know what to do.