A poo excreted in which requires no whiping afterwards, seeming as though it didnt occur in the first place.
A ghost poo usually tends to be hard (no smearing) and thick causing the anal rectum to enlarge and expand wide enough that it doesnt touch the hole, or the cheeks.
Andy thanked higher forces somewhere beyond our world knowing he was lucky that no wiping was required today for his grandfather Ernest. Ernest had a "ghost poo."
That new Ghostbusters 2016film was so much better than the original, and in itself, was so original and hilarious with very well managed comedy and action... Oh wait.