Many years ago, before Cloud Mountain erupted, raining fire upon the forest and scattering kilassin and tarasin alike in all directions, a broader variety of creatures roamed the jungles of Cularin. Some disappeared entirely when the fire rained down, but others simply relocated. One such creature was the dua-wurm.

Dua-wurms are rock-eaters who burrow through the underbelly of Cularin, extracting minerals from stone and earth. Before the eruption, the dua-wurms stayed well away from the molten rock beneath the mountain. But in the years following the eruption, many of the creatures gravitated to the newly stable, mineral-rich stone. The mining companies that eventually settled on Cularin found relatively little; most of the useful minerals had already been extracted by the wurms.

The wurms themselves proved quite a nuisance to the miners. Because of the speed with which they could burrow, dua-wurms could come up beneath a fresh tunnel and collapse it in an attempt to get at whatever trace minerals the machinery might otherwise have extracted. Droids were of little use against the dua-wurms, whose acid tended to fry the circuitry of even the hardiest of droid hunting parties, and many living beings who went deep into the mountain in search of the wurms either never returned or came back fewer in number than when they left.

The dua-wurm is a ferocious creature, quick to anger and quick to kill. It's not a natural predator of most creatures on Cularin, but it will attack if it feels at all threatened, biting with one of its two heads.

In an unfortunate act of physiology, the dua-wurm is not able to attack the same target with both of its heads, unless it's attacking something substantially bigger than itself. The angle at which its heads grow from its neck makes it impossible for the creature to orient both on the same person, though its brains are more than capable of coordinating attacks on multiple targets at the same time.

When fully grown, dua-wurms are 2 to 3 meters long and can weigh as much as 800 kilograms (they eat stone, after all). They are dark purple in color, and their skin is exceptionally tough, a mass of bruises and calluses developed as they scrape along the rocky underbelly of the mountain. Dua-wurms are typically solitary creatures, though there have been reports of a colony living in caverns deep below the mountain. Such a colony may well exist, since no one has ever seen a juvenile dua-wurm, and logic dictates that they must come from somewhere.