Little Mac is the protagonist from Mike Tyson's Punch-Out!! He is considered by many to be the ultimate underdog, as Mac battles his way through several boxers twice his size, until he gets to Mike Tyson himself.
He wouldn't be so lucky in the contests, however. In 2002, he was blown away by Link and didn't return until 2007. In 2007, Mac returned to lose to Dante and Amaterasu, but managed to KO Matt for third place. Good job Mac :D