Leon Lett’s Super Bowl Fumble (1993)
While it wasn’t as costly as some plays on this list, Cowboys defensive tackle Leon Lett committed an undeniably boneheaded blunder in Super Bowl XXVII. In the fourth quarter with a 35-point lead, Lett recovered Buffalo quarterback Frank Reich’s fumble and ran it back for over 60 yards, but he apparently let the score go to his head and started celebrating before he reached the goal line, allowing the Bills’ Don Beebe to swoop in and force Lett to fumble. The ball rolled through the back of the end zone for a touchback, but it was ultimately too little, too late for Buffalo.