Snowball fight. Sounds fun, doesn’t it? Kids hiding behind trees and pelting one another.

The term took on an entirely different meaning last Friday, however, when University of Oregon students took part in what might better be called a snowball brawl. A snowstorm that dumped 7 inches of snow in Eugene meant classes at the university were canceled Friday, giving thousands of students plenty of time to play outside.

Unfortunately, a relative few went beyond play.

According to the Register-Guard in Eugene, members of the university’s football team organized two snowball fights Friday. One, at Hayward Field, drew about 100 students and went off without incident.

The other, near Erb Memorial Union, was another matter.

There students, including UO football player Pharaoh Brown, became involved in something more sinister. Students surrounded at least two cars, preventing their drivers from moving. One driver, a former UO professor, got out of his car and was greeted with a bucket of snow in his face for his trouble. Listening to video tape of the incident, it sounds as ugly as it looks, with shouts and jeers and a clear mob mentality.

To date, the university’s response has been guarded. Brown, who is a tight end, has been barred from playing in the Alamo Bowl against Texas on Dec. 30. The football team’s coach, Mark Helfrich, says the school has begun disciplinary action against some other players. And the university police force, not city of Eugene police, is investigating.

It’s not the first time UO students have gone too far when it comes to having fun. There was a full-blown riot in September 2010 and a similar incident a couple of years earlier. In fact, there have been periodic riots clear back to the 1930s, some for political reasons, others fueled by alcohol or snow.

No one expects UO students to behave like angels. They’re young and many are away from home for the first time. At the same time, we should expect that play, including snowball fights, stays safe and playful.

Friday’s fight was neither. It might take an expulsion or two, but the university must help students understand the difference between a game and something far more sinister.