Hi Gibby. I have checked stool samples for parasites. I look for eggs, because that will be your first indication.
The poo contains a lot of stuff, you would be surprised.
Think about it like the sinus passage. All the mucus that can be produced. The bowel can be a mucus factory if there is something going on there. That means big chunks of gunk can be made, and dead tissue will shed as well. There are all sorts of things that go on chemically as well.
Worms will look like worms most of the time. They also have very distinct organs--even flukes. Shroom