Short answers, pulled from the story.
Mike Tyson was 20 years and 4 months old when he defeated Trevor Berbick by TKO on the 22nd of November 1986, making him the youngest heavyweight champion in boxing history, a record that still stands.
Tyson simultaneously held the WBA, WBC, and IBF heavyweight titles, becoming the first boxer ever to unify all three major belts at once. He won the WBC in November 1986, added the WBA in March 1987, and claimed the IBF in August 1987.
Tyson was knocked out 35 seconds into the tenth round in Tokyo on the 11th of February 1990, when Douglas landed an uppercut followed by a four-punch combination of hooks. Tyson had been a 42-to-1 betting favorite, making the loss one of the most shocking upsets in sports history.
Tyson was disqualified in the third round of the 28th of June 1997 rematch for biting Evander Holyfield on both ears. The first bite removed a piece of Holyfield's right ear; after a point deduction the fight resumed, but Tyson bit Holyfield again, prompting referee Mills Lane to stop the bout.
Tyson was convicted of rape on the 10th of February 1992, following a trial in Marion County, Indiana, and sentenced to six years in prison plus four years of probation. He served less than three years at the Indiana Youth Center and was released in March 1995.
Tyson's career knockout-to-win percentage is 88 percent. The Ring magazine ranked him 16th on its list of the 100 greatest punchers of all time, and ESPN ranked him first on its list of the hardest hitters in heavyweight history.