The owners of Goodrich Capital 8 Theaters in Jefferson City, Missouri, thought greeting Iron Man 3 audiences with people holding fake guns was a good idea.
The theater had a group of cosplayers dressed like members of S.H.I.E.L.D., the ficitious military branch featured in the movie.
The publicity stunt, though, went sour when customers panicked fearing a James Holmes copycat was storming the theater.
Several called the police, reporting seeing "a man in full assault gear, carrying what appeared to be a modified M-4 and 9 mm on his side."
ABC 17 interviewed Captain Doug Shoemaker, who was incredibly critical of the theater's decision:
"We received a series of 911 calls stating that a man dressed in all black and body armor and a rifle was walking into Capital 8 Theaters," said Capt. Doug Shoemaker.
Officers thought they were responding to an active shooter investigation.
"Everything was in place, it's the opening night of a superhero movie, it's somebody walking in all-dark clothes, everything pointed to bad things about to happen," said Shoemaker. "There's really no good that can come of this."
Bob Wilkins, the theater's manager, said that only a few moviegoers were upset by the stunt and that hundreds were entertained.
The theater seems to bring in a lot of cosplayers around the premieres of their movies, here's a Facebook album of some of the other events.
According to Captain Shoemaker, the biggest risk the theater took was not in scaring the audience, but causing someone to panic and fire a concealed weapon in self-defense.
Ryan Broderick is a reporter for BuzzFeed News and is based in London.
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