I to have been getting this out and like other ppl have commented, there is no definitive diagnosis as to what these things are and so we are all speculating. I accept that the medical paper which was circulated on here concerning Bacterial Rope parasites does depict images which are very similar, however, I am not sure if that is accurate as it is the only source I have found and they appear to have coined the term.
Having looked at it i think it is possible to visualise that as mucus coating which has either yeast/bacteraia proliferating in it which has coated a stretch of either the small or large intestine and has come away in a big piece (think of a snake skin shedding but in the case of the intestine this is in the reverse i.e. inside) and has come away. I wonder if you did a fast for a few days and took psyllium husk powder drinks whether it would move through the instestines and scratch/drag off the remaining coating given that you have clearly weakened a significant part of the biofilm.