B.o.B. Concert -- Fan Beaten By Security ... Video Shows Excessive Force

A B.o.B. fan got his ass whupped during a concert, and the security team continued beating the man long after he was subdued and cuffed.

It went down Sunday at KSFM's 102.5 Live concert in Sacramento. A fan aggressively charged the stage and seemed to just flip out on festival security. The team swarmed the guy and unloaded punch after punch.

Eventually, they took the guy behind a barrier where they thought they were shielded from the crowd. One of the guards decided to throw 2 extra punches to his face for good measure.

The fan was out of line in the first place, but there's no justification for the security guard gratuitously smacking the guy.