On April 30th, 1993, Monica Seles was winning a match 6 - 4, 4 - 3, when a Steffi Graf fan named Gunter Parche, came out of the stands and stabbed her between the shoulder blades. The obsessed fan tried to run away, but men in the crowd apprehended him until authorities arrived. Of course, Seles could not go on and ended up taking a hiatus before returning to tennis two years later.
On August 8th, 2011, Melza "CJ" Johnson, a player for the Arena Football team Georgia Force, was waiting to catch a kickoff when a Jacksonville Sharks fan grabbed him from behind. The fan held him there for a bit and even pulled at his face mask. CJ Johnson got away only to see the Sharks players - high five the man. The Force received the ball on the 20-yard line and went on to lose the game 64 to 55.
Drunken Patriots Fan
On November 3rd, 1961, the Patriots were winning by one touchdown. The Dallas Texans had the ball on the 5-yard line. A drunken man, who some claim was Patriots owner, Billy Sullivan, snuck onto the field. Cotton Davidson, the Texans quarterback, snapped the ball. The drunken man struck the ball down making the pass incomplete. The Patriots won, the fan got away with it, and no one knew until the following day.
During the eighth inning of game one of the 1996 American League Championship, the Yankees were losing to the Orioles by one. Derek Jeter hit a ball that would have been a tad short to be a home run. Orioles Tony Tarasco lost the opportunity to catch the ball when Jeffrey Maier, a 12-year-old boy, reached down and snatched the ball. The fan interference tied the game, which the Yankees would later win.
On October 14th, 2003, the Chicago Cubs were winning 3 to 0 going into the eighth inning against the Florida Marlins, with a 3 to 2 lead in the series. Steve Bartman deflected the foul ball of Luis Castillo that Moises Alou was ready to catch ensuring the second out of the inning leaving the Cubs only four outs away from breaking a curse. Instead, the Florida Marlins rallied and won.
Drunken Yankee Fan
On September 18th, 1993, 27 outs were all the Boston Red Sox needed to beat their rival the New York Yankees. Mike Greenwell caught what should have been the last out when the umpire called for the play to start over. As the pitch came in, a drunken Yankee fan ran onto the field. The fly out did not count and the Yankees got a boost and won.
In 2003, the Duke University basketball team was playing against North Carolina. Speedo Guy wanted to support Duke by distracting the players making free throws by jumping up wearing only a Speedo as they were shooting the ball. Of course, Jackie Manuel the North Carolina player could not concentrate, missing both free throws. In the end Duke won by three points.
Crowd of Reds Fans
During the fifth inning of the Milwaukee Brewers against Cincinnati Reds, Jay Bruce hit a deep drive into center field. Brewers' Lorenzo Cain jumped to get the ball and a crowd of Reds fans reached over the wall, redirecting it back onto the field. If Cain caught the ball, it would have been an out. Tim Welke, the crew chief, determined it was non-fan interference.
During the fifth inning of a Philadelphia Phillies and Chicago Cubs game in 2009, Shane Victorino ran to catch a fly ball. Suddenly a Cubs fan threw a beer at him, in hopes he would drop the ball. However, Victorino did not drop the ball. Instead, he made the play and the Phillies won the game 12 to 5. Still, the fan ruined the game, putting a stain on the behavior of Cubs' fans.
Fan in a Green Hat
During the fifth inning of a Pittsburgh Pirates and Milwaukee Brewers game, with two outs, Rob Mackowiak hit a pop fly into foul territory. Brewers' Tyler Houston attempted to catch the ball when a fan wearing a green hat caught it instead. Houston put on a good show trying to claim credit for the ball, but upon review, it was clear it was the gentleman in the green hat.