This is not an uncommon thing. The defense gets frustrated after finding itself down late in the game, leading it to make ill-advised decisions like throwing down a running back or quarterback as he runs out of bounds. What is uncommon, however, is this huge of a brawl occuring right after.
This is exactly what happened in an Indianapolis high school football game between Wayne South (Ind.) and Arsenal Tech. The latter was winning 24-6 in the third quarter when a scuffle started after a Wayne South defender slammed the running back while he was headed out of bounds. The scuffle got turned up a few notches when one of the coaches straight up decked another one. Fans got involved, and the fight soon got so bad that police had to be called in to break up the ruckus, ending the game.
It's a 42-second clip that got the two schools national recognition for all the wrong reasons and can potentially end their seasons if there's any sanctions.
[via Black Sports Online]