pranks

Because every Chemistry lecture could use a little bit of sword fighting, mariachi band, and heroism. WHO WAS THAT MASKED MAN.

Parents recently received this letter, it is believed to be a senior prank, to notify that their daughters were undergoing an "inspection".
This is similar to a flyer sent around to Lowell High School students:

Believe it or not, penis inspector Richard L. Dong is not real, and Lowell High School doesn't actually require its seniors to pass a penis inspection before they're allowed to graduate - rather, school officials believe the amusing fliers are just a senior prank orchestrated by members of the school's graduating class.

I bet the school janitor found this to be hilarious. Or not. OK probably definitely not.