Little Mac
From Nookipedia, the Animal Crossing wiki
Little Mac is the main character in the Punch-Out! series of games made by Nintendo. In the European version of Animal Crossing: City Folk he sends you a letter with the Green Headgear in it. The letter reads:
Dear <Player>, I've been training for my comeback and I need your help! Wear my headgear with pride so you can roll with the punches! From Little Mac
Although he sends this letter and item, he doesn't actually appear in the game.
