Mirko Filipovic
After winning the 2006 Pride Open-Weight Grand Prix, Mirko Filipovic was brought over to compete for the UFC Heavyweight Championship. However, Filipovic suffered an upset loss of epic proportions against Gabriel Gonzaga and hasn't been the same since.
With losses in his last two fights, Filipovic was nearly released from the UFC. However, the organization decided to give him one last chance, but Filipovic's days as a serious contender are clearly in the past.