There's a river near the place where i live but it's polluted and it's disgusting, and i just thought that it could be a node with a very filthy resonance and the tass it produces is literally garbage and other nasty stuff, and if you were to go into the umbra you would be able to see spirits of the wyrm living there, snake-like creatures, maybe even zombies feeding off tass in the shape of rotten meat (Because some people say that you can find dead bodies in there/So the tass is related to the "myths" surrounding the place), wraiths, ghosts this kind of thing and maybe a huge creature...