Paint an appropriately shaped large sweet potato brown and put it the toilet. I give it a dusting of instant coffee to produce the cloudy golden aura of a ripe floater. It is funny to see the response to the "terrible turd".
Wait til someone tries to flush that bad boy down, and causes a MAJOR clog! Lots of fun to be had!
It has been tried and tested. It doesn't create a clog as it is too big and rigid to get around the first bend, so it just floats back to the surface after all of the flushed water rushes by