Leon Spinks. He won the heavyweight title and a couple of other decent fights, then became a punching bag. He was knocked out in the first round by a man making his PRO DEBUT.
Hey C/A...... you know Im Boystovs biggest fan or anything, but you sold me on his age and his ability. He's young and still undefeated and has finally gotten outta that Universum debacle. I think Boystovs career has staled, but it's far from nosedived. If Pac loses to Rios, it's the gutter for a top 10 P4P ATG. Thats a fricking nosedive.:-(
6'2" & 245 lbs... sounds like he would have a chance against a Klitschko. And Guinn sure dropped off the map in a hurry.
Zab Judah? He may have not panned out to his full potential, but he was the last undisputed WW champion ever. To say he actually accomplished that would disqualify him from any discussion on the most disappointing career, in my opinion.