The dust mouse is a small creature found throughout Dadauar. Though it does resemble a mouse, the resemblance is superficial; dust mice are not true rodents, but magical creatures more closely related to mares than they are to mice. Dust mice do, however, behave much as mice do, and occupy the same niches, even to the extent of occasionally spreading into cities and invading buildings.
While the second part of the dust mouse's name may be inaccurate, the first part is not; dust mice are in fact literally made of dust, magically held together into their apparently murine form. They do eat grains and other similar foods, however, which their magical metabolic processes convert into dust, releasing energy as they do so. Their pulvereous composition is not obvious from their appearance, however; they simply resemble greyish mice; a few proportions are slightly off, the tail and snout longer than those of a true mouse and the ears set a little farther back, but except on a very close inspection the dust that makes them up can easily be mistaken for fine fur. The main giveaways are the eyes, feet, and tail, which in a real mouse are unfurred, while those of a dust mouse are the same greyish color and silky texture of the rest of the creature.
A dust mouse is very difficult to physically injure; if harmed, they can explode into puffs of dust, and later recoalesce into their usual forms, completely healed of any wounds they might have seemed to sustain. In fact, they may preemptively explode when threatened, to frustrate any attackers. If the dust is separated and prevented from rejoining, the dust mouse is effectively destroyed, but containing tiny moving dust particles is not a simple task.
Because of their unusual composition, dust mice have few natural enemies; most predators are not eager to dine on dust—though their resemblance to ordinary mice means carnivores do sometimes eat them by mistake. However, dust mice seem to rely on the ambient magic of their surroundings to hold themselves together, and anything that draws too deeply on that magic where the dust mouse is can disrupt its cohesion and destroy the mouse. Accordingly, dust mice are very rare within the onirarchies, where the dreamlords are making use of all available magic to fuel their own power. In some of the undeveloped nations, dust mice have become a serious problem; some cope by developing spells specifically to combat the dust mouse infestation, while others turn to the onirarchs for help, sending them food and other goods in return for their aid against the dust mice. The dreamlords are usually only too happy to oblige, drawing on the dream energy of the dust mice to further supplement their own power; the onirarchs of Seseal and Sineae, in particular, making something of a specialty of this, and turning the extermination of dust mice into a significant export.
It is widely believed that dust mice came into existence as a side effect of the onirarchs' large-scale siphoning of their subjects' dream energy —after all, if the onirarchs are the main force keeping the population down, then before their ascendance dust mice would have had nothing keeping their population in check, so their numbers would have exploded and they would have overrun the world—which, clearly, never happened. Some have even suggested that the dreamlords intentionally created the dust mice, as a further way to keep the undeveloped nations down without inconveniencing their own countries. However, there is much evidence that dust mice did exist before the onirarchs, so as attractive as this theory is, it seems incompatible with the facts. The best explanation anyone can come up with is that there was in fact some magical predator that fed on dust mice, but that it went extinct; the onirarchs didn't create dust mice, but rather (perhaps inadvertently) eradicated their predator. This still leaves uncertain, however, how dust mice (and their former predator) originally came to be, and whether they were some eccentric mage's creation in the distant past or whether they just came into existence as some fluke of uncontrolled magical interactions.