Giant slug is a type of monster in ADOM. They are very slow beasts that have a quite powerful acid breath attack. They are highly vulnerable to fire-based attacks. Their corpses are notable for granting a full elemental immunity, rather than a resistance. Giant slugs generally do not show up until around the middle of the game, though some are usually found in Keethrax's level in the Druid Dungeon. Low levelled PCs in particular should watch out for their breath; though this does come in useful for clearing out hostile cats.