Slugs are slimy giant slug creatures that inhabit the Golden Hills. They are treated as pests by the Dwarves there and often attack each other. In later games, it would seem the minions have turned them into a good source of food.
The smaller and more common slug variety, with only one eyestalk and a small poison spit attack. They tend to spawn endlessly from holes in the ground, marked by green smoke coming out.
SlugThe far larger variety of slug, with 3 eyes and the ability to eat large objects whole. If it catches a minion, that minion is eaten whole within seconds. Often only found underground, after Goldo has been defeated, a migration near the first Tower Gate can sometimes happen with a large Slug and smaller Sluglets.
A huge slug found in the tunnels of the Arcanium Mine. She lies right in front of a slug nursery, this nursery only dries up if you defeat her. A strategy for beating her is bringing her to the fires near the Smelter. Turning it off and sweeping reds through the fires, she will stay on the flames and burn alive.
Treasure Slug (Conjecture name)
In the Golden Abyss, a sluglet has had a bag of gold strapped onto it and wanders in a circle with demented Dwarves following after it.
Some of the larger varieties can regenerate from remains of the magical ooze left after briefly killing them and can release ooze whilst in combat. Strangely enemies killed by the magical ooze will have a chance to spawn as a mutant slug.
The Mutated Slugs only appear in Overlord II.