1. When you poop into a toilet and turn around to admire your creation only to find nothing in the toilet bowl
2. When your poop disappears into the depths of the toilet without being seen.
3. A poop where the only evidence of its existence is something you felt or heard. There is no concrete physical evidence to be found.
I like to take pictures of my turds and text them to my friend Trevor, when I stood up to snap a pic of my latest creation I was shocked to see I just encountered a ghost poop.
My Grandmother has a very old toilet that sits at a weird angle. The poop slides right down the drain, so 3 out of every 5 poops are ghost poops.