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.
An orc male who dislikes the hard warrior life, has disguised himself as an orc female and is learning how to become a Shaman. If uncovered as a male, his fellow orcs will be disgusted enough to kill him.