Giant Slugs are typically a dull grey with a corpse-like pallor to their underside. The result of a mutation in an ordinary slug, the resulting omnivorous monstrosity has an enormous appetite and quickly develops a preference for flesh and bone. Smaller creatures are too nimble and fast for it to catch, so it targets larger mammals, such as humanoids and livestock. The Giant Slug has thick, rubbery flesh that is resistant to all bludgeoning damage and is deceptively flexible, able to squeeze its bulk through a space as narrow as five feet. The creature leaves a slick trail of slime as it moves and is able to disgorge copious sprays of potent digestive acid onto its prey as well as deliver a vicious bite with its fang covered radula. They also have a very nasty surprise for any large creature that gets too close, as they can fire a harpoon-like chitinous spear into a creature they are adjacent to.

Giant slugs roam constantly until they find a rich source of food, hunting the area clean, they also eat vegetation and have a wide tolerance for environments that are not too hot, cold or dry. The stats for an aquatic giant slug are exactly the same as the terrestrial version, except they lack the potent acid spray.