San Francisco 49ers fans must be stopped. The fanbase has become known for inciting violence against other fans in the NFL, most recently when one Niners fan started a major brawl in Arizona during Week 3. It only got worse this week during a game against the Kansas City Chiefs. 

As you'll see in the video above, they've now started throwing punches among themselves. The clip was taken in a men's bathroom in Levi's Stadium this past weekend, showing what appears to be a completely random act of violence, as one San Francisco fans decks another supporter of the team, causing the man to hit the concrete in a full KO. The video title states that the unconscious man may have received brain damage from the blow. 

According to Alex C, the YouTube user who uploaded the video, the fight was the, "first thing that happened when entering bathroom. All due to impatience for an open stall."

Yikes. Fan fights can range from funny to horrifying, but this particular tussle seems openly sadistic, provided there were no extenuating circumstances beyond what we see in the video.