This slug like parasite is actually a symbiote. After attaching itself to a warmblooded host, it feeds off that being. However, its tenticles, growing under the skin, act as secondary nerves, increase the victims nerve responses.
The Black Forest- actually a part of another forest, is said to be cursed by the presence of some horrific monster, which burns the very earth with its body!
No one has yet seen it and lived to tell, so be warned!(see NPC Aurelius Blackfoot for details)