Geno is a magical living doll first appearing in Super Mario RPG, and he is also a character in the Bowser's Kingdom show.
In Episode 6, Geno asks his friend Mallow if they made it into a cartoon, but Mallow tells him they didn't because Rick Finkelstein didn't get Super Mario RPG references. Geno tells Mallow that he should show them why he's so awesome by blowing up the unemployment office, but Mallow isn't impressed by this and claims he's going to tell Mario. Geno tells Mallow to shut up before convincing him to go in search of some "Birdo snout" which they can "f*ck".
Geno reappeared in Episode 666, as one of the few survivors of the zombie invasion and taking refuge in a castle on the Doughnut Plains. He explains to Hal and Jeff that the outbreak occurred because a company wanted to invent an umbrella that could repair itself upon being torn, but something went terribly wrong during the development, and everyone turned into zombies. Big Boo is unconvinced, claiming that Geno's story is a "fat load of shit". When the zombies invade the castle, Geno is swallowed by a zombified Steve the Piranha Plant, but in one of the two separate endings, he uses a powerful magic beam to destroy Steve from the inside and obliterate the other zombies. After the victory, Geno boasts of his awesomeness.