The robot form of Knuckles the Echidna has had few appearances throughout the series, but is still an unarguably badass bot. As he debuted in the Saturn racing game Sonic R, Metal Knuckles is to Knuckles what Metal Sonic is to Sonic.... obviously. Outfitted with claws that can break through stone, massive strength, jets for far superior gliding, and just-as-good speed, Metal Knuckles is statistically superior to his meat-filled fuzzy red counterpart. However, nothing can beat the mind of the original. While the main red version of the Metal Knuckles model has yet to appear outside Sonic R, he has had a later incarnation in Sonic Advance, often known as Mecha Knuckles. He is a little different, at first being disguised as the real Knuckles, and being broken down into an unpainted, gray metal model. Despite such, the idea of a robot version of Knuckles is still beyond badass, and many fans have clamored for a return of the menacing rad red robot - one that delivers.