Tlic

The Tlic are a sapient alien species which begin life as endoparasitoidic larvae.

Biology
Adult Tlic are large creatures, about 3 meters long, with a segmented body and at least eight limbs, all of which are equally dexterous except for the final few. Their undersides have a velvet-like texture. They have a long whip-like tail with a stinger that can release a soporific substance, and their limbs are equipped with sharp claws that can slash a man's throat in a single strike. Their saliva has properties that help heal wounds and prevent blood loss.

Despite their arthropod-like appearance, Tlic are vertebrates with an internal skeleton consisting of skull, spine, ribs and four sets of limbbones per segment. Their movements are swift and fluid, however, and have been compared to the movements of aquatic invertebrates. They enjoy being in physical contact with Humans because of the latter's body heat, indicating that the Tlic might be poikilothermic. Compared to Humans, Tlic can see better in darkness.

Female Tlic live much longer than Humans. Males, on the other hand, are short-lived, and reach their adult stage while the females are yet to go through their metamorphosis.

Reproduction
Tlic are parasitoids which implant eggs inside a warm-blooded host using an ovipositor. The ovipositor also produces a narcotic substance that soothes the host-to-be, which helps the implantation process. They can also produce sterile eggs filled with this same narcotic, which can be consumed by Humans and seem to have beneficial effects on their health, extending Human life and promoting vitality.

Once inside the host, Tlic eggs cling to the host's blood vessels with a tube or hook-shaped projection, taking in the host's blood to feed the young larvae. When the larvae are ready, they release toxins that signal that they're about to hatch. At this point, they consume their egg cases and go on to consume the host's flesh, killing the host in the process. Once they emerge, they bury themselves back and keep on feeding until there's nothing left for them.

It is possible to surgically extract the Tlic larvae during the time after they start consuming their egg cases and before they start consuming the host's flesh. In order to survive, the larvae can be transferred to the body of a recently-slain animal, providing them with enough food to move on to their next life stage. Hosts who have survived this process can even be implanted again in the future.

Tlic larvae are grub-like, with neither bones nor limbs, and still have to pass through a metamorphosis before reaching their adult stage.

Tlic find Humans to be extraordinarily suitable hosts. When other species are implanted, it is a common occurrence for only one or two of the Tlic larvae to emerge, while in Humans, all larvae tend to survive until they emerge. Tlic who are born from Humans also grow to be larger and healthier than most of their brethren.

Appearances

 * "Bloodchild", by Octavia E. Butler (1984)