Stone-eater

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

Description
Adult stone-eaters looked similar to slug-like formations of lava rock. They were between 30 and 100 feet (9.1 and 30.5 meters) long, although it is rumored that they can grow much larger. They were covered in a skin of solid rock which could be up to 5 feet (1.5 meters) thick and was riddled with rifts and cracks. Only their heads, which were generally about 2 feet (0.6 meters) in diameter, were exposed.

Abilities
From their heads and the cracks in their skin, they 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. 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), their tunnels would quickly collapse. Fresh tunnels continued to radiate heat for up to a day, and pools of acid would collect on the floors.

Combat
In combat, stone-eaters were slow, and generally content to let their ever-present heat take care of any 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, they 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 native to underground regions, and could be found in the Underdark. They were long-lived, and laid eggs only about twice a millennium. These eggs had the appearance of small boulders which radiated intense heat and oozed acid, which pooled around them and ate into whatever surface on which they were laid. This created snug niches into which the eggs receded before hatching. Eggs were often laid in small, deep caverns into which the stone-eater took care to only create one entrance, and were known to be laid in clutches of three. A newly hatched stone-eater might be no larger that 1 foot (0.3 meters) in length.

Uses
Stone-eater eggs were highly prized by alchemists, and were rare enough to be greatly valued by scholars of magic.

Some underground cultures, especially those of evil persuasion, 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 spears through the fissures in their rocky skin to jab the sensitive flesh beneath. This job of prodding and herding the stone-eaters was incredibly dangerous. In duergar society, these herders were called "horgarin."

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 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.

Appearances

 * Adventures
 * The Mines of Bloodstone