Prior to my parents launching their own business my dad worked for a company that is now out of business. At the time he was an engineer and on the design team for the type of product that they made. (Sorry stalkers but that is all you get)
My father would often tell of one of the greatest mysteries at this job and that was the Phantom Sh*tter. This guy apparently never got caught to the mystery remains as to who he was. We can only assume he was male as the men's room was the only target, of course it is possible for a woman to have sneaked in.
The Phantom Sh*tter would wipe feces on the walls of the bathroom stalls as if to somehow form some kind of meaningful expression. It would be said "The Phantom Sh*tter struck again." and people would go investigate out of curiosity. One of the attempts to bring the Phantom to justice was the use of video cameras, such a rare thing in that time period of the 80's. DNA testing was not available back then and most certainly a Phantom Sh*tter would be much easier to catch in today's world of modern technology.
If the Phantom Sh*tter ever reads this post, allow me to convey my father's words to you. May your feces always be brown and sticky so that the world can continue to marvel at your works of art.