The Tosoks are a sapient spacefaring species which made first contact with humanity in the late twentieth century. They are native to the Alpha Centauri System and are notable for their natural ability to hibernate for centuries, which has facilitated the species' achievement of interstellar traveling.
Tosoks are about five and a half feet tall, with a dome-like head and four radially arranged limbs protruding from below it. The left and right limbs are longer, with three joints, and act as legs. The front and rear ones are shorter and act as arms, these terminating in four fingers with flattened tips. The arms aren't symmetrical, though, as the front one is far more robust than the rear one.
The head sports two mouths (one on the front, one on the back); two pairs of convex circular eyes (one on the front above the front arm, and the other on the back above the rear arm); two pairs of ear slits; a pair of breathing orifices on the sides; and a tuft of white tendrils on the top which move in complex patterns to express emotion and gestures. The mouth is a horizontal slit which opens to reveal a secondary vertical opening, and two tongues.
The Tosok skin is made up of small diamond-shaped scales and molts regularly. Their skin color varies from blue to grey to silver-white depending on the individual, and often changes color after molding. In most Tosoks, each of the four eyes is of a different color, although some individuals may have two or more eyes of the same color. The eye coloration seems to be completely random in this species.
Tosoks are omnivorous creatures, although they no longer hunt animals for meat, preferring to produce it in laboratory. They breathe oxygen and require roughly the same environmental conditions as a Human being. Although carbon-based, their genetic material differs from DNA and stores information in a binary-like code, determined by the presence or absence of methyl groups.
Relatively little has been revealed about their internal workings, as they consider the subject as a taboo, analogous to how Humans tend to view sex. It is known that they are vertebrates and have four hearts, each covered by a hemispherical lung. Their blood contains structures for carrying oxygen, repairing tissue and fighting off infection, much like Human blood, but it also contains something referred to as "free-floating nerve components" which presumably transport information to the nervous system. These are produced by a large organ called kivart, which holds great medical importance, being one of the only major organs of which they have only one, rather than four.
Tosok blood solidifies into pink crystals when exposed, in order to fasten up healing. Lead is extremely poisonous to them. They are capable of regenerating limbs and organs and may live for extended periods of time with only two hearts and lungs, rather than four.
Despite being naturally omnivorous, Tosoks no longer kill wildlife for meat, as they have means of artificially replicating it. Their eating habits have been described as "fascinating" as well as "disgusting". They wear clothes, with numerous pockets, and have a peculiar speech pattern which consists of starting each sentence in a low volume and pronouncing it progressively louder until the end, before starting a new one.
Although they show no embarrassment over being naked or molting, the inner workings of the body are considered an extremely unpleasant taboo, which should only be discussed in the presence of a priest-physician. Their psychology is mostly human-like, but there are a few aspects of Earth entertainment which are incomprehensible to them, such as roller-coasters and similar rides, and the concept of anthropomorphic animals as characters.
Tosok society is peaceful and mostly devoid of crime. They are also monotheistic, believing in a foremother God figure. One major aspect in which Tosok psychology differs from Human is that they strongly believe in predestination and thus have no concepts of morality. As everything that happens is due to the will of the God, one cannot act rightly or wrongly. If one were to do something that was against the will of the God, then the God would prevent them beforehand. Everything that already happened is thus considered God's will.
Tosoks formerly believed themselves to have been created in perfect image of the God, but the discovery of evolution has since shattered this belief. Nevertheless, they are still convinced that somewhere in the universe live the actual children of the God, and intend to contact them.
The Tosok homeworld performs a highly complex, but stable, orbit around its binary suns, causing it to alternate every four thousand years between going around Alpha Centauri A and Alpha Centauri B, due to the disturbance provoked by Proxima Centauri. Life can only exist on its surface while it's orbiting A. The much dimmer light of B causes the planet's entire biosphere to go into a prolonged state of hibernation. Hence the Tosoks' natural ability to go in stasis for several thousands of years.
As the Tosok civilization achieved a higher technological stage, they started intercepting radio signals from other stars, leading them to realize that they weren't alone in the universe. Realizing that the long periods of hibernation imposed on their species every four thousand years would make them vulnerable to hostile aliens, the Tosoks started sending vessels to all nearby star system intending to preemptively annihilate their cosmic neighbors to assure their safety. One such vessel encountered the "Twirlers", a technologically superior race, which responded to the Tosoks' violent attack on their own homeworld. Soon war erupted, with at least two other civilizations allying with the Twirlers. With their combined powers they managed to subdue the attackers, devastating the Tosok homeworld and taking the survivors to a galactic trial where they would be charged with genocide.
- Illegal Alien, by Robert J. Sawyer (1997)