School spirit is a wonderful attribute for a university. We certainly have it in abundance at Penn State.

There are few things that make me prouder than seeing 110,000 cheering students and alumni on football Saturdays, proclaiming their love and loyalty for the university, or the thousands who attend basketball games, volleyball matches, homecoming parades, and our dance marathon, the world’s largest student-run philanthropy.

But there can be a dark side. Over the weekend Penn State beat Ohio State in a football game with possible implications for the national championship. I helped stir the crowd of alumni and students at a pep rally in Columbus beforehand, even playing the bass drum with our pep band. It was good, clean fun, as they say. How could a president be prouder of our fans, not to mention the team and coaching staff?

Yet I suspected what was coming. After we intercepted a pass to clinch the victory, my colleagues and I immediately turned our attention to “the aftermath”: A “riot” might be overstating what happened, and “celebratory disturbance” might be a euphemism. But whatever you call it, it wasn’t acceptable to me or to anyone else who cares about the university, public safety, and decorum.

We’ve seen this before, earlier in my presidency, but not in recent years. Thousands of students poured into the streets of our university town to celebrate. But somewhere in that group were a few bad apples, unquestionably excited by the victory and undoubtedly lubricated with alcohol. They tore down two light poles and some signs, smashed a police-car window, and threw debris at the police.

In the overall scheme of things the damage wasn’t profound, but the behavior was disturbing. Police officers trying to keep order were threatened. Unruly crowds posed safety hazards. It wasn’t a proud moment.

There are two kinds of people who pour into the streets, the voyeurs and the hooligans. Many don’t know beforehand which category they will fall into. More than 95 percent are the voyeurs, but for a few, excitement turns to exuberance, exuberance to hostility, hostility to destruction.

But guess what the police were doing on Sunday? The same thing I was doing. Watching the dozens of videos posted on YouTube by the voyeurs. Nowadays most everything seems to be captured on camera by fellow students. Some students and their parents will be very sorry about what is shown in the videos.

Meanwhile, the police are grateful for this new enforcement vehicle. Arrests will be made for the property destruction, perpetrators will be fully disciplined, and we’ll hope that school spirit can be expressed in the future with greater civility and social responsibility.