Police in Teaneck, N.J., arrested 60 high school seniors for breaking into their school, flipping desks, peeing in hallways and greasing doorknobs.
The teens allegedly organized a massive senior prank, but police are calling it criminal mischief and burglary.
Authorities responded to Teaneck High School around 2:30 a.m. when an alarm was tripped. The building was trashed, with balloons and streamers littering the urine-soaked halls.
They found some students hiding inside and others trying to run away.
So many were involved in the prank that 10 different law enforcement agencies had to make several trips to get them all to the police station.
"I've been a police officer 19 years and this is the craziest thing I've ever seen," Teaneck Police Sgt. John Garland told NBC New York.
Of the 60 arrested, 24 are 18 years old and will have to appear in court. They were released into their parents' custody.
Class is still being held Thursday, Teaneck High School Principal Dennis Heck said.