A couple of high school senior pranksters in Minnesota are being investigated after fake letters ordering senior female students to attend a "mandatory vagina inspection."

The letter cleverly written on an official-looking letterhead for Prior Lake High School in Savage, were delivered to at least 50 families. It warned girls to remove any accessories such as piercings before undergoing the examination. The fake letters also threatened to stop students from graduating if they didn't attend the examination. The prank went viral with millions of people seeing the funny side.

The Daily News reports that the school district representative Kristi Mussman told the Minneapolis Star-Tribune that the joke was "done in extremely poor taste."