Someone has requested MORE information about a disgusting wormy thing! I can hardly contain my joy!
I should qualify all this by saying that I'm not at all sure
that's a lump of bryozoans, just my best guess. I wasn't aware they'd recoil from light like that, or more probably, heat. They are animals, though, and can move.
Assuming they are bryozoans, each of those lumpy bits is a colony of many. They spawn sort of spore-style, like corals, so it would be quite likely for them to find a spot in each of those junctions. Also, I don't think that pipe is very big, actually, but bryozoan colonies can form disturbingly jiggly, large, free floating mats of crud.
You can see a few pictures here
, but there are hundreds and hundreds of kinds, and they're all really different.
I just googled North Carolina sewer life and found something saying it's tubifex worms, but I dunno. I think those are just the little red worms that you feed goldfish...maybe there's more than one kind.
I could keep going, but surely this is more than enough to kill the thread.