The video pretty much explains it all, but here’s more from the guys at Eleven Warriors, which covers OSU football:

Many ‘oohs’ and ‘ahhs’ came from the estimated 2,500 students watching on either sideline. The student portraying the loveable nut popped right back up but quickly left. He was not seen again. There’s no word on whether he suffered an injury or if it was only his pride that was hurt.  Following practice, Perkins said he didn’t mean to hit Brutus so hard. But when a linebacker sees a ball carrier streaking down the field untouched, the juices get flowing.