Dating Sim Mario
Okay, so it's not really a job, but it is a genre of video games. Though rarely encountered outside Japan, where no one bats an eye at dudes reading hentai on the subway, a dating simulator is really the perfect game for Mario.
Imagine the shenanigans as the stocky Italian tries to summarize exactly what he does in round after round of speed dating. "I'm a plumber. I really hate turtles. Sometimes I put on a cape and run around the Mushroom Kingdom. My best friends are a dinosaur and a talking toadstool." Plus, he's been obsessed with the same girl for decades now. And he's probably still a virgin. Hilarity!