It only took a few hours for a "friendly snowball fight" at the University of Oregon to devolve into a potentially criminal assault on innocent bystanders and passing motorists.
The fight, organized by the school's football team to mark the first serious snowfall of the season, started just after noon on Friday.
But footage uploaded to YouTube later that day shows it didn't remain friendly for long.
The Daily Emerald reports that by 3 p.m., the fight had "turned rowdy," with students pelting passing cars with snowballs, and physically blocking the vehicles' path.
Retired UO professor Sherwin Simmons had an entire bucket of snow dumped on him as he exited his car to confront his attackers.
In response to the video's spread on social networks, UO's dean of students Paul Shang released a statement saying UO's police department was investigating the incident and may bring charges against those involved.
"Police hope to determine the identities of those who were throwing snowballs, whether they are UO students and whether their actions constitute a criminal act," Shang said in his statement.
A petition posted on Change.org which calls on the school to "carry out deep disciplinary action against those who participated in snow-fighting frenzy" has nearly reached its goal of 500 signatures.
Meanwhile, Andre Yruretagoyena, offensive lineman for the Oregon Ducks, took to Twitter to express disappointment at his teammates' behavior.
"Embarrassed by the video I just watched," he tweeted. "That’s not all of us, sending the sincerest apologies."
For his part, Prof. Simmons said he will not be pressing charges.
"I have confidence that the reaction of the university given what has happened will be proportional," he told the Emerald. "It will consider these young people and their futures and will also, I hope, suggest to them that they need to rethink behavior like that."