Officials at Ashwaubenon High School said a concerned parent called police after seeing someone walk into the school with unusual clothing, according to WITI-TV. The costume was in celebration of May 4th, also known as "May the Fourth Be With You Day," inspired by the Lucas films' catchphrase "May the Force be with you."
Ashwaubenon Public Safety responded to the scene and evacuated the high school. Parkview Middle School and the Community Center, where some students were taking an AP test, were put into lockdown.
Public Safety officials did a sweep through the high school -- and no threat was found.
While the incident turned out to be an innocent mix-up, Principal Brian Nelsen noted that wearing a costume at school was against the rules, according to WLUK-TV.
"There was no legitimate threat at AHS. It was a misunderstanding where a student wore a Star Wars costume for 'May the Fourth Be With You' day. There was no intent of a threat, but the student will be held accountable," said Ashwaubenon School District said in a Facebook post.