The main one that came to mind for me was Danny Williams v Matt Skelton where he seemed to think that getting as big as he could would give him a power advantage.

Danny comes in at 16lbs heavier than he's ever fought, and was so slow he could barely catch Skelton to hit him, and Skelton's plan of boxing Williams and staying out of trouble works a dream, and is a nightmare for spectators. I know, I nearly cut my wrists late in the fight, but the edge of the plastic seats at the Millenium stadium aren't sharp enough.