A person who takes a monstrous dump in a public bathroom and doesn't flush. Usually there is a posse of poopers like this (a Brick Layer's union) who will build an unflushable wall of turds. This is mainly done to offend people and piss them and the janitor off.
I was going to take a shit at the Dollar General crapper, but a bunch of brick layers had been there and clogged the toilet up. I admired their pile and wished I could lay such a brick but sadly, I haven't had a solid turd in years.