This massive wormlike creature of burnt iron and glistening hematite grinds with the roar of the forge. Its fanged lamprey like mouth opens to reveal the molten fires burning in its gut.
AC 36, touch 8, flat-footed 34 (+2 Dex, +28 natural, -4 size)
Str 41, Dex 14, Con 26, Int 18, Wis 19, Cha 10
Whenever a slag worm moves at least half of its speed in a single round it creates a grinding roar of metal on metal from its body. Creatures within 50 feet that hear this grinding roar must succeed on a DC 30 Fortitude save or be deafened for 2d4 rounds. The save DC is Constitution-based.
A slag worm’s body generates intense heat. Anything within 10 feet of its body takes 4d6 points of fire damage each round. A DC 30 Fortitude save reduces the damage by half. Any weapon that strikes a slag worm must succeed on a DC 30 Fortitude save or melt into slag. (Magic weapons gain their enhancement bonus to their save.) A creature striking a slag worm with a natural attack or unarmed takes the same 4d6 points of damage each time an attack hits. The save DCs are Constitution-based.
Fire deals no damage to a slag worm. Instead, the slag worm absorbs the effect and heals 1 point of damage for each 3 points the effect would otherwise deal. If the amount of healing would cause the slag worm to exceed its full normal hit points, it gains any excess as temporary hit points.
Attacks that cause rusting (such as a rusting grasp spell or the touch of a rust monster) deal 2d6 points of damage to a slag worm.
Environment any (Elemental Planes of Earth, Elemental Planes of Fire, Plane of Molten Skies)
Slag worms burrow endlessly through the elemental Plane of Earth, Elemental Planes of Fire, and Plane of Molten Skies, occasionally forcing through weak points into the material planes where they burrow deep beneath the earth, devouring raw iron deposits to keep their internal furnaces burning. Because of this they have been known to devour entire companies of heavily armored dwarves and orcs, mistaking their gear for a new vein of naturally occurring iron salts.
Slag worms average about 40 feet long and weigh about 60,000 pounds, though specimens as large as 100 feet or more have been rumored to exist. Its massive form radiates abysmal heat and when the worm opens its maw, fires can be seen burning and raging in its interior. They are intelligent creatures (more so than their appearance of a big dumb worm would lead one to believe) and can speak though they rarely choose to converse with other races.
A slag worm erupts from the ground seeking to eat anything wearing iron, steel, or other metal armor or equipment. It attacks such creatures with a great ferocity, generally disregarding other enemies until the worm is heavily injured or forced away by magic.
Slag Worm from the Tome of Horrors Complete, Copyright 2011, Necromancer Games, Inc., published and distributed by Frog God Games; Author Scott Greene.