It was November 3rd, 1961, and the fledgling American Football League was just over a year old, when the Dallas Texans (who later became the Kansas City Chiefs) visited the Boston Patriots, and lost on one of the most bizarre final plays in sports history.

Down 28-21 with seconds on the clock, the Texans completed a 70-yard pass on a flea flicker to put them on Boston’s 3-yard line. Thousands of Pats fans rushed the field thinking the game was over, but the referee signaled that there was enough time on the clock for one more play, and the crowd was ushered to the sidelines.

Now, you know how home fans like to get into the action when their team is mounting a goal-line stand, but one anonymous onlooker took it a little further. Just before the snap, he ran into the end zone and lined up behind the Pats’ linebackers.

Dallas QB Cotton Davidson spotted receiver Chris Burford wide open in the end zone, but the “12th man” put a stop to the potential game-tying touchdown by deflecting the pass and scampering off the field before officials even noticed he was there. No one on the Patriots noticed either, but they surely would’ve given the mystery fan a game ball for his staunch goal-line defense.