The Achatina muscaria, more commonly known as the Giant African Ghoul Slug, measures 21 inches long when stretched out. It has been to known to be deadly to a wide variety of large animals, including lions, wildebeests, chimpanzees, and people. It's slimy body releases a hallucinogenic ooze when it moves, and animals that come into contact with it (usually by stepping into it by accident),experience and discover the meaning to life, and shortly thereafter die from ecstasy. The slug then enters the victims stomachs through the oral cavity, and feasts on the contents of it's stomach and intestines, and then devours the liver, stomach, and intestines, in that order. The slug cannot produce it's own shell, so it uses the skeletal remains of it's victims as such. They can use a wide variety of bony parts, but by far, it's favorite is the human skull. Because of this, the animal has been associated with the devil in many South African religions, for the toxins it releases produces a great euphoric feeling, followed by death shortly after, similar to the actions of many demons. However, the animal can only kill by the ooze it leaves behind, so the slug itself is not only safe to eat, but considered a delicacy by many, especially considering it's large size. Some cultures also raise these slugs in captivity, and carefully collect the ooze, and sell it to people in diluted quantities. The ooze itself is a psychoaddictive drug but generally non-fatal in small quantities, and in some countries the use and sale of these drugs is illlegal.
Reference for the skull, http://img530.imageshack.us/img530/6135/humanskull.jpg