If you don't know the nuances of the "Harry Potter" world, Dementors are evil magical beings that fly around in black cloaks and suck all of the happiness out of good people. Good children's stuff there, J.K. Rowling.

Anyway, on Tuesday, someone in Essexville, Michigan called the police to report a Dementor flying around a park.

The person was serious about it, but when police investigated, it turned out to be a black garbage bag stuck in a tree. The cops were nice enough not to arrest the person who called for wasting their time.