User blog comment:MetalShadow272/The Missing Links of Sonic History./@comment-2147834-20110607004436/@comment-1986314-20110607100119

Metal Knux never appeared in the comics, and Tails Doll made two cameo appearances in StH 134.

But yeah, it's a bit similar to Geno and Mallow, but in Nintendo, they like to forget characters all the time.