An elementary school in Walpole, Massachusetts , has canceled its annual Halloween parade, leading hundreds of residents to sign an online petition to save the tradition.

Instead of wearing costumes to class, students at Elm Street School will celebrate with a black-and-orange spirit day on Friday. Parents say the decision was made with little warning, leaving them without enough time to plan an alternative after-school event.

“The principal sent out a note in one of her newsletters saying costumes are not allowed,” parent Liz Campbell told CBS News . “But the actual parade being canceled was word of mouth through the children.”

Among those affected is six-year-old Charlie, who was eager to show off his Super Mario costume to his teachers and classmates.

Frustrated families quickly launched an online petition on Monday to preserve the parade, gathering nearly 400 signatures from current and past Walpole parents.

Parents in Walpole, Massachusetts, are making a last-minute effort to save an elementary…