MORGANZA, Md. (AP) — Some seniors at a Maryland school aren’t feeling lucky, despite ladybugs that swarmed the halls.

Six Chopticon High School seniors face charges, and WTTG-TV in Washington reported one is banned from walking in Wednesday’s graduation.

The St. Mary’s County Sheriff’s Office said someone ordered 72,000 ladybugs online. Sgt. Cara Grimbles told the TV station that a door was forced early on May 20, setting off an alarm and taking this “to a different level.”

Deputies said the seniors and an alumnus are responsible. Four minors are charged with burglary, destruction of property and disrupting school activities. Deputies will charge three adults by criminal summons.

Senior Brian Reminga pleaded with administrators via WTTG: “Please let me walk. It was a harmless prank.”

One student was disciplined after school officials evaluated all factors in each case, said Michael Wyant, director of safety and security for county schools.

“We certainly realize senior pranks are expected and normal at this time of year, and we try to be tolerant of that,” Wyant said. “But there are boundaries we need to maintain.”

He said officials consider whether an event represented a danger to students, damaged a school or had cleanup costs.

 More innocuous pranks have included spelling out a school name in letters on a field using plastic utensils and covering a school van in plastic wrap.

In this case, if police had responded and not school building services staffers, they may not have known it was a prank, Wyant said.

It took seven employees about four hours to clean up the ladybugs, but Wyant said they weren’t counting how many were gathered. Asked if all the bugs were gone, Wyant said: “No way.”