Slugs belong to the phylum of molluscs, in the class Gastropoda, which are soft-bodied invertebrate animals.
Slugs are related to snails, but do not have a shell. All slugs have a protective coat of slime and a distinctive head with protruding tentacles, which have eyes at the end. The tentacles are used to smell and locate food.
Slugs eat plants so they are a great pest in the vegetable garden; some species are carnivorous and eat other slugs, snails, and earthworms.