Upon first inspection, though not looking too closely, it did appear as though it was a genuine organism, some kind of mutant waste sprung to life by the abomination that is American stuff, but I decided to watch the video again and I am pretty sure that they really are just large clusters of random sewer worms huddling together, cloaked by some very slimy, slimy, slime.
Edit: :< Ephi proved my theory.