BOULDER, Colo. — A University of Colorado student is accused of pulling an insensitive prank that got him into some serious trouble Sunday night.

Witnesses say the teen put on a “Joker” mask inside a Century theater in Boulder, causing a panic. The supposed prank earned the 17-year-old a spot in a juvenile detention facility Monday morning.

He is a minor, so police aren’t releasing his name. He told authorities his actions were nothing more than an innocent prank. 

But witnesses who bolted from the theater afraid for their safety say it wasn’t funny at all, especially considering the “Joker” is the same Batman character that suspect James Holmes portrayed when he opened fire on a crowded Aurora theater, killing 12 and injuring 58 others in July.

The 17-year-old told police he put on a clown hat and the Joker mask just to scare his friends, not everyone else. But police say several people saw the get-up and feared for their safety.

The theater manager called police. They quickly tracked down the part-time CU student, who was carrying the mask that he said he hopes to wear for Halloween next year in a shopping bag.

He didn’t have a weapon and didn’t make any threats. But because five people felt they were in danger because of his actions, the teen is being charged with five counts of menacing, a misdemeanor that may involve a fine and several months in custody.