look up any word, like hipster:
 
1.
The act of taking a poop, in which you know you pooped, however, there is nothing in the toilet bowl to flush except the bum wipe.
Mystery Poop is one of those unsolved mysteries.
by Poohzie May 27, 2009
 
2.
to go into a freshly cleaned public restroom, dropping a fat deuce, not flushing, and exiting the restroom unidentified.
someone dropped a fat deuce in my restroom the other day. It must have been the mystery pooper!
by TheMysteryPooper December 28, 2010
 
3.
After performing the act of dropping a deuce, refers to the absence of leftover feces about the buttocks. Therefore, leaving nothing behind to wipe. It's a mystery.
I love mystery poops, there's nothing to clean up after.
by Long-Dong Silver September 16, 2008