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.
You meet a large number of villagers, walking and weeping beside the coffin of an old bearded man (or adapt to your funeral customs). If asked properly, you learn about an old wizard, a wise man that long helped the tiny village to grow and prosper. Even after death he shows his favour: he gave most of his possesions to the poorer members of the community. All the villagers show him now respect this way. Why do you ask, are you adventurers? (As a last wish, he left a tiny case for the first group of adventurers that crosses the village).