Stone-eater

Stone-eaters, known as horgar in Dwarvish and storgin in Gnomish, were dangerous subterranean creatures known for tunneling through solid rock with the use of heat and acid.

Description
Stone-eaters looked similar to slug-like formations of lava rock. Adults grew up to in length, although it was rumored that they could grow even larger. They were covered in a skin of solid rock, which could be up to thick and was riddled with rifts and cracks. Only their heads, which were generally about in diameter, were exposed, and even this exposed flesh had a stone-like quality.

Stone-eaters smelled strongly of super-heated ammonia, which tended to irritate nearby creatures' eyes, noses, and throats. At all times, it was surrounded by the faint hissing sound of its acid dissolving whatever the stone-eater was touching. When it moved, its skin made the sound of rocks grating on rock.

Abilities
From their heads and the cracks in their skin, stone-eaters exuded pure acid which they used to "eat" through solid rock along with help from their incredibly high body temperatures, often exceeding 400 to 500 degrees Fahrenheit (204 to 260 degrees Celsius).

Behavior
Stone-eaters burrowed slowly through the rock with little malice or concern for whatever was in their path. In fact, they could hardly tell when a living creature (or that creature's home) was in its way, and simply moved forward regardless. Their acid and heat would eat away at rock and then fuse it into tunnels behind them, although when travelling through softer rock (such as sandstone), these tunnels would quickly collapse. Fresh tunnels were incredibly hot in the first several hours after the stone-eater carved them, so much so that wood could ignite just by touching the tunnel walls. These tunnels continued to radiate warmth for up to a day, and pools of acid would collect on the floors.

Combat
Stone-eaters preferred to avoid confrontations, and would generally leave creatures alone if attacked. That said, they did not exactly flee from attackers given that they were quite slow and their ever-present heat could kill most attackers while their solid skin and oozing acid kept them safe. Nonmagical edged weapons would dull quickly against their skin, and any nonmagical weapon, tool, or flesh that touched them began to be dissolved by their potent acid. Naturally, stone-eaters were completely immune to any fire- or acid-based attacks, and likewise were known to shrug off electricity as well.

If provoked, or if its exposed head was threatened, a stone-eater could spit its acid up to 20 feet (6.1 meters) with remarkable accuracy.

Ecology
Stone-eaters were solitary creatures native to deep underground regions of hard rock, and could be found in the Underdark. They were long-lived, and their waste products included breathable gasses, liquefied rocks, and mineral deposits, all of which were valuable to the inhabitants of the Underdark above and beyond the utility of the tunnels carved by the stone-eaters.

Stone-eaters laid eggs only about twice a millennium. These eggs literally split off of the stone-eater's body, shrinking it. The eggs had the appearance of small boulders which radiated intense heat and oozed acid,. This acid would pool around them and eat into the surface on which they were laid, creating snug niches into which the eggs receded before hatching. Eggs were often laid in clutches of between two and twenty, and were hidden inside small, deep caverns into which the stone-eater took care to create only one entrance. A newly hatched stone-eater was about in length.

Uses
Stone-eater eggs were highly prized by alchemists, and were rare enough to be greatly valued by scholars of magic. Pieces of adult stone-eaters had value to wizards with specialization in magic relating to digging and heat.

Some underground cultures, including dwarves and deep gnomes but especially duergar and drow, were known to domesticate stone-eaters for their eggs or for use in both tunneling and combat. The creatures were housed in glass-lined pits, and were herded by inserting very narrow glass spears through the fissures in their rocky skin to jab the sensitive flesh beneath. In dwarven society, these herders were called "horgarin." This job of prodding and herding the stone-eaters was incredibly dangerous, and some dwarves had a saying, "as unlucky as a horgarin without a spear."

History
Given the great danger posed by these creatures, as well as their role in carving the tunnels and caverns used for travel and shelter by the races of the Underdark, it was not uncommon for stone-eaters to be viewed with awe and reverence by primitive subterranean cultures. Some even believed that stone-eaters were responsible for the carving of the whole of the Underdark.

Notable Stone-Eaters
In the mid–14 century DR, an long stone-eater dwelt in the caverns beneath the Bloodstone Mines in Damara, where it had laid a clutch of three eggs.

Appearances

 * Adventures
 * The Mines of Bloodstone