I remember in college (early 00s when music piracy was huge) someone set up a site where you could enter an email and it’d send them a fake letter from the RIAA about the downloading they were doing.

Sent one to my college roommate and sat quietly while he got home from class and checked his email. He obviously started panicking until the link in the email revealed the joke. He didn’t think it was funny and swore cold blooded revenge that I’ve yet to receive. Still keep one eye open at night.