Slugs are a shell-less terrestrial gastropod mollusc snails. Slugs are cold and slimy animals. The skin of a slug is exceptionally moist, and often covered in a thin layer of slimy mucus which make them move on the ground. The mucus helps it to retain moisture to the dry soil beneath them and protects it from most predators, which dislike the taste. Slugs have two pair of tentacles on their head. The upper pair is light sensing and has eyespots at the ends to allow for vision, but they also contain olfactory organs as well while the lower pair are used as feelers and taste buds. Both pairs are retractable and can be operated independently. A slug can smell you and a friend simultaneously. Hidden under a slug’s tentacles is the mouth, which opens to release a radula. The radula is a tongue-like organ that has teeth-like protrusions that help it saw through food before ingestion.