Sports fandom is great for many reasons. It facilitates social connections, both those relationships that last a long time (like friendships fueled by shared fandom) and the more ephemeral connections with strangers sporting your team’s laundry. It provides an escape from the stresses of everyday life. It can even inspire you to exercise. We’ve seen time and time again how fandom can uplift society.

But it’s a double-edged sword. Fandom also has downsides. Exhibit A: the fight between fans at Saturday’s Steelers-Lions preseason game at Heinz Field.

Aggression often boils over in the stands, whether we’re talking about games in the United States or aborad. In European football, hooliganism that results in murder has long been an issue. Group rivalry has also proven fatal stateside, as we saw in July when a fight between a Giants fan and Eagles fan in Philadelphia turned deadly.

Fortunately, brawls in the crowd at sporting events usually don’t have such negative repercussions. Nonetheless, they are a major black eye of the sports industry—something we all should agree makes for a less pleasurable consumption experience. Let’s recount the 15 craziest fan brawls at sporting events in recent years.