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.
A master thief is struck by an insanity spell and thinks he is half cat. He walks around sniffing things, clawing the furniture and licking himself in the manner of a grooming cat. This is a major cause of embarassment to the guild and the master thief must be cured of his insanity.