SPORT: Boxing
YEARS ACTIVE: 1981 to 2005
COMPLEX SAYS: The welterweight was a six-time world champion during his career and still has the record for longest undefeated streak in boxing history: 13 years, 11 months, and 24 days. With 86 knockouts in his career, they ain't call him Mr. KO for nothing. Too bad he retired before he could shut Floyd the fuck up.