Anyone know what a mucus cast is and if its a symptom of IBS?

I saw something in my stool a few times which looks like a raggedy worm - been goggling today and it says it could be a Rope Worm but then i listened to a video which convinced me Rope Worm was a hoax. And one of the posts calling Rope Worm "a quack" was by a parasitologist who said he'd seen a few of these musuc plugs before. Another site called them mucus casts. I can't really work out why i would have it though or if it's anything to worry about. 

I also get occasional steatorrhea and i have diorrhea most of the time, go to loo regularly. Am taking VSL#3 probiotics at the moment though and feeling a lot better on them altho still bloated which is a side effect of VSL#3. Hoping i just have SIBO but worried i could be coeliac also. 

Ask for a test for SIBO and celiac to allievate your worries.  Do you have any abdominal pain? Mucus in your stool is an IBS symptom.  Ask about IBS.