These are pieces of mucoid plaque. This is how we refer to them here at Curezone. People doing The Master Cleanse pass these ropes plenty (check the Master-Cleanse forum). They are chunks of biofilm (covering the intestinal lining) and the dead flora which used to live in there(candida included). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930275/