A slug, or land slug, is a common name for any terrestrial gastropod mollusk that appears to lack a shell. The term “slug” is often used to describe any gastropod mollusk that has no shell, a significantly reduced shell, or only a small internal shell. This is particularly true for sea slugs and semi-slugs. In contrast, the term “snail” refers to gastropods that possess a coiled shell large enough for them to fully retract their soft bodies into it.
