No doubt it's Jim Marshall with the wrong way run. Sanchez's butt fumble was a hilariously honest mistake, while Jim Marshall running the ball back against his own team is just completely unforgivable. Not only did he run the ball back in his own team's endzone, but he threw the ball in celebration and cost them a safety.
Surprisingly, it didn't cost the Vikings the game. I also highly doubt that the Jets would have been able to upend the Patriots in the butt-fumble game anyways.
Bigger March Madness upset: 1983 North Carolina State (over Houston) or 1985 Villanova (over Georgetown) ???