Acidnids are pretty rare yet common at the same time. Finding one is hard, but if you see one, there are many more behind. Acidnids release a liquidy acidic saliva from there mouth that hardens into a string-like substance, when in string form however it loses its acidic touch.
There very agressive, so k!lling one is hard enough, if not including the whole cluster.

#-Hyper-rebooT-