ugghh, that is gross. That is one thing I don't miss about teaching in elementary, poop. I had one student poop their pants and it looked like he had a poop pancake in his shorts. Almost puked.
But this is a better story. The gym teacher had kindergartners doing warmups and he smelled something. He had all kids stop and check the bottom of their shoes for dog poo. Everyone was clean. He checked his shoes and he had stepped in a turd in class. A kindergartner had managed to poop and shake it out his pantleg and the teacher stepped in it. Here's the kicker, someone from the same gradelevel did the same thing a year later. The culprit is still unknown and we refer to him as the "phantom pooper".