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Mike Tyson

1988-90

Becoming the youngest heavyweight titlist in history at age 20 by knocking out Trevor Berbick in 1986, Tyson went on to unify two more titles to set up a showdown with lineal champion Michael Spinks in 1988. In the crowning moment of his career, "Iron Mike" crushed the undefeated Spinks in just 91 seconds.

Tyson went on to make just two more defenses before being upset in 1990 by unheralded James "Buster" Douglas in Tokyo. After serving nearly three years in prison for a rape conviction, Tyson returned to collect a pair of titles before being upset again by a rejuvenated Evander Holyfield in 1996.