Psitticoids of Theta Apodis IV
Despite actually being a type of fungus, convergent evolution led these creatures to strongly resemble Earth parrots. Their psionic skills, in particular their mind control abilities, allowed the Psitticoids to carve out a modest empire and drive their rivals the Daurians to extinction. Accordingly, they dispatched a long-range infiltration cruiser to Earth, to begin controlling key subjects in preparation for all-out invasion.
The Psitticoids were defeated due to mankind’s propensity for putting parrots in cages; without direct contact, they were only able to repeat garbled fragments of human thoughts–just like Earth parrots. Their ability to lower the intelligence of nearby creatures similarly went unnoticed, as people tend to behave childishly around pets anyway. Most of the Psitticoid 112th Infiltration Unit currently resides in an illegal Manhattan pet shop specializing in exotic birds.
Capricornians from Deneb Algedi II
The harsh climate of Deneb Algedi II led to a species that can conduct and ground electricity with an insulative coating that must be periodically shed. This has the side effect of making them incredibly deadly warriors as well as highly similar in appearance to Earthborne sheep. After subduing their own homeworld and enslaving the Ovidines of HD 20644b, the Capricornians launched a full-scale invasion of Earth.
Unfortunately, their assault craft landed on a rainy day in New Zealand. Unable to use their discharge powers for fear of electrocution, they were inadvertently sheared by sheep farmers and deprived of their primary weapon. The herd was culled later that month, with all the surviving Capricornians winding up slain and mixed in with animal fodder. Their presence was only discovered after a rash of exploding wool shirts and temporarily electrified sheep.
Apids from Musca Australis Prime
Broadly resembling terrestrial insects, the Apids are highly coordinated and toxic creatures made up of hundreds of small organisms that are specialized (not unlike the Portuguese Man-o’-War). With a neural net formed of Apids and pheromones at the center of each swarm, they easily overwhelmed all comers in establishing domination over their sector.
Their scouting party on Earth met a tragic fate when a human swatted the Apid that was responsible for navigating the swarm. Without direction, it wandered through an air intake and was shredded. The incident was only noticed when the highly corrosive remains ate through the intake and the surrounding city blocks.
Aurigans from the Almaaz Dark Disc
These mysterious creatures evolved in an environment so strikingly different from Earth as to be inconceivable not only to humans but all other species on this list. Uniquely, they evolved a cylindrical layout which allowed them to roll along the surface of objects they encountered, along with a hollow core to allow interstellar debris to pass through and dark coloring to blend in with the light-absorbing matter in the Dark Disc. They communicate with bioluminescence along their outer rims, relying on a network of photoreceptor grooves on their outer surface to pick up sensory information, the pattern of which is unique to each Aurigan.
Just like their evolution, the Aurigans’ motivations are inscrutable, and they have annihilated several species nearby while leaving others untouched. What is known is that a party of Aurigans landed on Earth, undetected by the authorities. Unfortunately for them, they landed in Detroit (which even the Apids knew to avoid), touching down in an urban tire yard. Thanks to their unique morphology, the Aurigans’ corpses are still attached to the rims of a 1989 Honda Civic.
Excerpts From Nonexistent Books 