Androbious reptiles native to Nadayal but also found in many other planes of the Parasite World. Gnatscales are sex feeders with bizarre and somewhat extreme sexual dimorphism, with males and females not only very different in size but also in diet. The species is androbious only by a technicality, as the females exclusively feed on male prey while the males exclusively feed on female prey, each with very different hunting methods.

Common traits shared between male and female gnatscales are their hollow claws, head-tendrils, additional tails, and complete lack of teeth, although some sub-species of gnatscales found on layers below Nadayal are known to possess fangs or full sets of retractable teeth. Their claws are usable for self-defense but are mainly utilized while hunting, connected to glands that produce an aphrodisiac venom and acting more like fangs than proper claws. Their head-tendrils are also used while hunting and - alongside the extra tails - for communication.

Both sexes have extremely sharp senses of smell and sight, even possessing extra nostrils to pass more air over their sensitive nerves without overwhelming the animals. They can even detect subtler smells like pheromones and hormones in the air from a large distance away. By contrast, however, their hearing is mediocre at best.

Considerably smaller and more robust than females, male gnatscales tend to be scarcely larger than Prime World geckos, and tend to move in short high-speed bursts. They are stalking predators that hunt in a small area. Once suitable prey is found, they will stalk the prey and then pounce.

As incubi, they exclusively feed on females, but they are somewhat more picky about their prey than other incubi. Gnatscales strongly prefer highly developed prey with large breasts, often middle-aged or near middle-aged. This preference means they will hunt sapient, bipedal prey at a much higher frequency than most incubi would, as it is most often bipeds that meet this criteria.

Once the male makes contact with prey, it will rapidly make its way to one of the prey's breasts, setting itself on top and digging in with its claws hard enough to break skin. The claws then begin injecting venom that rapidly stimulates lactation and sexual arousal, but also acts as an orgasm-blocker; making it very difficult (albeit not impossible) for the prey to orgasm. The male gnatscale then places its mouth over the prey's nipple and begins drinking, its saliva greatly increasing skin sensitivity while further increasing milk production. The males tend to gorge themselves when feeding, continually doing so for days or on some occasions for weeks. When feeding, the male enters a rapid digestion cycle that quickly turns ingested milk into stored fat, further increasing how long it can spend feeding before full.

Removing a feeding male gnatscale is very difficult and ill-advised. They have remarkably malleable bodies that flatten while latched on, making them difficult to grip, while their undersides and head-tendrils produce powerful suction. Additionally, successful removal invariably causes deep and painful lacerations to the prey's breasts due to the gnatscale's claws, while the removal stresses the gnatscale and causes it to flood the prey with venom. This overdose of venom can cause painful episodes of over-lactation and edging that can last for days before subsiding, and in rare cases can even be fatal.

At the same time, however, gnatscale feeding is especially prone to attracting other incubi, as the days-long edging effect of their venom causes the prey's smell to become much easier to detect. This can be especially problematic if an arrowbird is attracted. The nonstop orgasm effects of arrowbird saliva and edging effects of gnatscale venom are known to interact, causing orgasms to become overwhelming, bordering on painful, while extending the effects of both aphrodisiacs.

Roughly the size of Prime World Great Danes, female gnatscales are extremely fast ambush hunters, capable of identifying prey from a large distance away and using their lithe, greyhound-like bodies to move through dense foliage with surprising stealth.

Once females have identified prey, they attack quickly with their claws, using stabbing strikes (as opposed to slashing) to inject large doses of venom, and then retreat. After retreating, they watch and stalk the prey from a distance as the venom takes hold. The male prey under the effect of the venom will experience continually increasing arousal and orgasm-denial, preventing the prey from relieving themselves via masturbation. Additionally, the venom temporarily rewires the prey's brain to sexually imprint on female gnatscales. How intense this effect becomes varies by individual, but it will sometimes progress to the point that the prey can think about nothing but fucking the female gnatscale that attacked him.

Once the prey is ready - either ready to feed the gnatscale willingly or too delirious and incapacitated to resist - the gnatscale moves in and begins fellating the prey to feed on his semen. The gnatscale's thick saliva further arouses and stimulates the prey while the gnatscale's surprisingly strong and elastic head-tendrils prevent escape (as well as providing convenient handlebars for willing prey). Additionally, the saliva creates a seal around the prey's penis that allows movement but makes complete separation difficult. This is coupled with the gnatscale's muscular gums and throat, both of which are specialized for sexual stimulation.

Female gnatscales tend to feed off and on for hours at a time, and are intelligent enough to limit their use of venom, allowing the prey enough movement to find water before dosing them again, and will sometimes position themselves specifically to allow movement, although their bulk and the effects of feeding ensure the prey won't move far and won't be able to effectively resist.