"The umber brown spitting slug produces an acidic slime, which it both secretes and hawks at its adversaries."
Spits ranged acid at opponents, which also leaves a permanent 4x3 acid pool on impact.
They will also explode into a permanent pool of acid when defeated.
The acid pools left behind by their attacks and corpses block the movement of other creatures and hinder auto-exploration in narrow corridors. They can either be dug around or be burned away with Flaming Hands, Thermal Grenades or other heat sources.