In Mike Tyson’s Punch-Out!!, King Hippo is a boxer from Hippo Island. Both his girth and face resemble a hippopotamus. He has helpfully taped an X over his belly, which gives Mac a target to aim for when trying to hit King Hippo’s weak spot.
In the Nintendo series Punch-Out!!, Little Mac is a scrappy underdog boxer who’s trained with Doc Louis. He’s worked his way up from the bottom to face Mike Tyson, Mr. Dream, and even make an appearance in the next Super Smash Bros.