I too experience this intriguing phenomenon occasionally and have wondered what exactly it may be.  These things do not look like something that would naturally occur in a person, right?  They appear to be plastic or something.  The only thing I can imagine is that a very large enteric coated pill somehow makes it through both the small and large intestines getting coated with something else along the way.  What medications do you take that may fit this description?

I sometimes have what looks like peanuts in my stool. Have no idea what it is. I see a gastroenterologist Monday morning to find out. I also have stabbing stomach pains right before a bowel movement and gas.