"Sickly nodes are what you get when you take all nodes away from an area and it tries to make more to replace them. Hungry nodes are what you get when you pile a lot of nodes on top of each other in the same location. The nodes start - stealing essence from each other, fighting. Eventually one wins, and eats its fellows. Except after, it's - used to being fed. And then it starts eating more. The after effect is very like a sickly node, in that it eats the essence of things, but it is much, much, much better at it, and feeding it more essence doesn't fix it. You can destroy them, but I don't have the materials to do so yet. The essence potion doesn't help, the node just chews through it in about three seconds and then gets to eating you. I know where two are, I stay far, far away from them. At least until I can kill them."