All things considered, freestyle wrestling is a pretty clean sport, and violence and angry outbursts aren't a regular part of competition. But then losing temper is a human trait, and it could happen to anyone anywhere, especially if you're getting your butt kicked, or in this case, manhandled.
The footage below is from a Russian freestyle wrestling match that took place at Far Eastern Federal University in Vladivostok, Russia. The guy in red was getting dominated by the guy in blue, and it seems this must have been going on for quite some time. It got to a point where the sore loser completely lost it and turned this freestyle wrestling bout into an MMA bout.
Unluckily for him, his opponent was just as adept at all-out fighting. Having failed at a takedown attempt, the guy in red started throwing slaps and kicks, but he couldn't do much damage. Meanwhile, his opponent floored him with a single kick to the groin before all hell broke loose.
The two opponents' cronies came barging in and suddenly everyone was beating everyone. Several other guys can be seen getting warmed up, but match officials were able to restore peace.