Thesserex Scatha




Photosynthertic Omnivorous Lithotroph


9-10 ft.


12-15 ft.


12-15 ft.







Thesserexes (thes-uh-recks), also known as Star Demons, are dangerous aerial omnivores native to the interstellar void.

Thessrex swarms have been known to annihilate all life on entire planets due to their feeding frenzies. They are intelligent enough to burrow into the hulls of starships and stowaway in order to hitch a ride to star systems they cannot reach as quickly.


Thesserexes are extremely durable creatures. They are virtually immune to radiation, extreme temperatures, and have no need to breathe. They have advanced mitochondria that produce much more energy than those of humans human. Their tissue is extremely toxic to humans; exposure to blood or other fluids will quickly kill most carbon-based lifeforms, due to high levels of arsenic. This has led some xenobiologists to speculate that they are in fact nitrogen-arsenic based organisms, although this is unconfirmed.

Their wings are used to collect solar energy, which is then converted into the energy necessary to fuel their biological ion-drive located in the tail. Openings along the sides of the tail allow for the expulsion of undigested matter in the form of pressurized gas, allowing them to control their trajectory in the vacuum of space. Although traveling at sub-light speeds, this, combined with their near-immortal lifespans and other biological improbabilities, allows them to travel between star systems.

The thesserex is a true omnivore, able to digest animal tissue, plant matter, and minerals, as well as being photosynthetic. They locate prey via specialized cells that line the creatures' mandibles; these cells are in fact highly electrosensitive, allowing thesserexes to detect lifeforms across hundreds of feet, perhaps even miles. This has led to rumors that the creatures are psychic, although this is a misconception.

When living prey isn't present, they will latch onto any available mineral source with a prehensile tongue. This tongue is equipped with a secondary mouth, and is lined with eight stinger-tipped tentacles. The thesserex will then proceed to dissolve the minerals with its' acidic saliva, turning it into a muddy pulp which is then sucked into the tongue and digested.

Due to their unique biological make up, thesserexes are even able to survive entering and exiting a planets' atmosphere. They must do this in order to reproduce, since their young cannot survive in space until maturity.


Thesserexes are highly intelligent and social. They travel through the void in swarms that can include up to hundreds of individuals; there are rumors of swarms of thousands of individuals reported, but these remain unconfirmed. Thessrex swarms move in perfect unison due to their electrosensitivity, which allows them to detect the movements of their fellows. They are occasionally seen encircling stars in order to charge their biological ion-drives, and are frequently seen around large asteroid fields.

When it is time to mate, whole swarms will descend on a planet. First, they will devour anything not larger than themselves, but will use coordinated group attacks to bring down larger prey. After the feeding frenzy, the hermaphroditic thessrexes will mate in midair, much like hawks. Each will fertilize the other, and will then lay about ten eggs in a massive communal nest, leading to tens of thousands of thessrex hatchlings. The adults will then depart, leaving the young to fend for themselves.

Once the eggs hatch, a colossal swarm of ravenous thessrex hatchlings will emerge to devour everything in sight. The frenzy will last much longer than that of the adults. This period typically lasts 1-2 years, although reports of longer frenzies have surfaced. This can devastate the local ecological balance; some planets may never recover from the massive loss of life.

Like the bees of earth, thessrex communicate via movement. Their complex aerial manuvers communicate potential food sources as welll as dangers such as black holes. It is also curious to note that thesserexes mate for life, as well as mourn their dead.


Due to its' adaptability, population range, and need to reproduce on-planet, the thesserex has developed into several subspecies that remain on their planet of origin. It is theorized that some slight genetic mutation left some ancient thesserexes unable to leave their planet, but still able to reproduce. These thesserexes continued to reproduce and evolve, leading to these subspecies.

Umbral ThesserexEdit


Umbral Thesserex

Little has changed for the umbral thesserex besides its' appearance and inability to leave the planet. Unlike its' ancestor, however, this subspecies produces a potent neurotoxin in its' tail. It will then fly over its' prey, spraying the toxin via the gas vents located on the tail, killing its' prey almost instantly. Also unlike its' ancestor, this thesserex is largely solitary and bioluminescent. They are found on Charon. Charonites are immune to the toxins of the creatures. A caste of Charonites called Skyriders use Umbral Thesserexes as mounts, sometimes in battle.

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