EIDELONS / SEBACEANS

Planet of Origin: Arnessk, in the Milky Way galaxy, which they inahbited 12 000 years ago until the planet became inhabitable due an alien attack..

The Eidelons is an advanced pacifist humanoid species which possesses a gland in their head that  acts as an empathic receptor, allowing the Eidelon to sense the wants and desires of those nearby, and vibrates to create an energy field which helps them develop tranquility and rationality. Using these powers, the ancient Eidelons could devise compromises that met the goals of the involved conflicting parties and could ensure that a peaceful solution to conflicts would be accepted. Eidelons look remarkably like humans but have an internal very different cranial structure, being able to open up the upper part of their head when their gland is in action.

Looking for a species to serve both as bodyguards and as enforcers of peace. They abducted primitve humans on planet Earth some  27,000 years ago and genetically enhanced them. This new species became known as the Sebaceans and they became the Eidelons' trusted acolytes. They took on the name of Peacekeepers due to their function.

After Arnessk became uninhabitable and the Eidelons has vanished (either fleeing to other planets or entering suspended animation outside of time. The Peacekeepers attempted to carry and kept the peace with military force, and eventually became the militaristic Peacekeeper empire.Today, only a handful of Eidelons remain.

SOurce: Farscape Universe.

STARRO / STAR CONQUEROR

Sentient starfish-shaped alien species with a central eye and prehensile extremities. They are also known as Star Conquerors. Adult Starro can asexually generate parasitic clones from their own body and command them to act in accordance with his will. Although equipped with only limited mobility, Starro parasites can attach themselves to a victim's face, whereupon they attack a body's central nervous system, subsequently taking control of both their mind and body, acting as transmitters of the adult starro's will. A Starro parasite can maintain control over its victim for an extended period of time, forcing them to obey their every whim, even if it goes against the nature of the selected target. This ability only works so long as the parasite maintains physical contact with its victim. Once the parasite is removed, the victim regains control of their mind and motor function.

Starro can absorb energy and rechannel it as powerful blasts of energy, which it directs through the tip of each tentacle and generate energy fielsd allowing them flight in both outer space and atmospheric environments.A fully grown Starro is impervious to most conventional forms of attack. Gunfire and similar weapons are ineffective against a Starro. Starro can also change the color of its skin for different purposes,

The first passage of a Starro on Earth happened in 1960. It was destroyed shortly after its arrival but surviving fragments managed to redevelop sentiance afterward from time to time.

Source: DC Universe. The character first appeared in Brave and the Bold #28 (Feb. - March 1960), Starro the Conqueror was created by writer Gardner Fox and artist Mike Sekowsky. The Starro species was further developed by writer Grant Morrison.

THASIANS

Planet of Origin: Thasus, a dry planet within 1000 light years from Earth

Thasians are non-corporeal entities with powerful psychokynetic powers which they can transmit to others (as it was the cae in the 23th century when they rescued a young human boy whose parents spaceship crashlanded on their planet.

Source: Star Trek universe (TOS: "Charlie X")

FIRST FEDERATION

Planet of Origin: A planet orbiting Fesarius, a K Orange star less than a thousand light years from Earth.

The First Federation members are one meter tall bald humanoids who developed a peaceful yet recluse and non-expansive highly advanced spacefaring civilisation. Their territorial space is surrounded by a network of space buoys and contact with other species are usually dealt with kilometers wide spherical one-man ships, leading to believe that space travel remains rare among the species. 

First contact with humanity was made in 2226.

Source: Star Trek universe (TOS: "The Corbomite Maneuver")

GALAXIANS /GALAXIENS

Planet of Origin: Original planet unknown. After it underwent a critical greenhouse effect some 2000 years ago. Three quarter of the population left in space arks and relocated on the First of the two moons of planet Aktarka, orbiting a G star in the Milky Way. A minority of Galaxians stayed on their homeworld but all contact was lost with the exilees.

The Galaxians are a pacific, even  friendly, species of one meter tall humanoids that have developed an advanced but ot expansive interstellar space-faring civilisation. Their skin was originally of a light orangeish color, but after their planet was exposed to heavier sun exposition, they slowly turned s to black over generations. Those who relocated to Aktarka's moon turned to green skin. All quite ressemble bald teddy bears. A minority, mainly among females, have been known to develop psychic powers.

Galaxian society is very democratic, one with a constant )sometimes even daily) exchange of social tasks even in the sharing of tasks. The annual head of state is called the Prince-of-the-Year and is the Galaxian who received the most merit points over the past year.

Over him is the Council of Elders which is made up of five Galaxian patriarchs which seems to be an half-honorific title for those chosen as they dont always seem to have much credit given to them.  The younger Galaxians are quite aware of their elders deficiencies and often take them half-serously. 

Source: The Scrameustache series, by Gos and Walt

OVIONS

Ovions are a four-armed bipedal man-sized insectoid species that were members of the Cylon Alliance to whow Their tylium mines were an extremely valuable asset.  They manage a Gambling ans entertainment complex on the surface of their homeworld to attract preys. Individual humans are trapped selectively and taken into the hive-like structures underground  to be placed into chambers which slowly transform them into food. Ovions occasionally prowl discreetly on the entertainment level, but generally remain out of sight. 

They are now presumably extinct since their world was destroyed in the explosion of their tylium mines.

Source: Battlestar Galactica Universe  (Saga of a Star World). 

AQUANS

Planet of Origin: Argo,  a seismically-unstable planet. Once a land planet, but its surface became almost completely covered by water, following a series of violent seismic disturbances, leaving only a single large landmass, with a few associated outcroppings.

The Aquan are an humanoid species which developed an advanced planetbound civilisation. They are good example of forced evolution as originally air-breathers were they mutated themselves to become able to breath underwater after massive planet-wide earthquakes flooded the entire planet.

They are governed by the Ruling tribunal of the Anquans and follow the Aquan Ordainment, an ancient set of rules.

Source: Star Trek Universe,  (TAS: "The Ambergris Element") 

SHANSHEETH

The Shansheeth are species of avian bipeds. Two meters tall, they have hunched shoulders with a long neck protruding from the middle section of their body and a vulture like head. They have five digits clawed hands and feet. Apart of their head, neck, feet and hands, most of their body is covered in feathers. They are able to project energy beams from their hands and like wearing robes and jewels.

A peaceful advanced space faring civilisation led by a political enitiy known as the Wide Wing of the High Shansheeth Nest, they have been known amongst the interstellar community as galactic undertakers, journeying through space in tribal groups to return lost heroes to their kin. .They employ shards of black stones called epitaph sotnes which they use to project hologrphic images to communicate with other species and  have also been known to use devieces called memory weaves to extracting memories and turning them into physical objects.

 Source: Doctor Who Universe (SJA: Death of the Doctor) 

QETESH

The Qetesh is a species that developed an advanced civilisation capable of star travel. They feed off powerfukl emotions such as excitement in people's lives, draining their life essence with it and are therefore masters of emotional manipulation ot achieve sustainance. They are also known as "soul-stealers".

Their stomachs existed outside their bodies, and they did not need air to breathe. The mobile part of their body has been known to look human, but they are most proabably albe to make it match the appearance of their prey's nature to better manipulate them into generating emotionnal food.

Source: Doctor Who Universe (SJA: Goodbye, Sarah Jane Smith)

FLESHKIND

Planet of Origin: Fleshking planet, part of a binary planetary system (the other planet being the Metalkind planet) in the eye of the Tornado Nebula.

The Fleshkind is a carbon-based humanoid species that developed an advanced civilisation and possesses interstellar-range teleportation technology as well as advanced genetic engineering. 

They are externally almost undistinguishable from humans but can shoot energetic discharges from their hands to place others in a trance. Given the fact that they have been known to develop living weapons of high destructive power, this ability might have been engineered.

The Fleshlkind was at war with a Metalkind race that lived on the twin planet of their homeworld after they started mining operations to mine precious ore on  the Metalkind planet; ore which was in fact the the Metalkind's children. Discovering this fact, the Fleshkind started using the so-captured Metalkind as slaves, which lead to the war.

Th war had come to a stalemate as of the beginning of the 21st century when the Flehskind developed a living weapon capable to destroying all the Metalkind but the weapon was lost, possibly restoring the stalemate.

Source: Doctor Who Universe (SJA: Sky)

METALKIND

Planet of Origin: Metalking planet, part of a binary planetary system (the other planet being the Fleshkind planet) in the eye of the Tornado Nebula.

The Metalkind is a species of sentient  humanoid bio-metalloid  boron-based lifeforms. The Metalkind was at war with a Fleshkind race that lived on the twin planet of their homeworld after they started mining operations to mine precious ore on  the Metalkind planet; ore which was in fact the the Metalkind's children - which were then used as slaves by the Flehskind, leading to the war.

This leads to believe that the Fleshkind was originally more technologically advanced than the Metalkind, being the first one to venture on the other's planet and starting its exploitation. As of the 21st century, after hubndreds of years of war, both species possessed weapons that enabled some kind of stalemate bwetween them, as well as interstellar-range teleportation technology - which might have been the initial way the Fleshkind made it to the Matlakind planet.

To end the stalemate, the Fleshkind had developed a  living weapon that could destroy the Metalkind but the weapon was lost, possibly restoring the stalemate.

Source: Doctor Who Universe, (SJA: Sky)

VENDORIANS

Planet of Origin: Vendor (Vendoria)

An advanced cephalopodic sentient, tentacled shape-shifting species.  In their natural form, Vendorians look rather like floating orange lamps adorned with six trailing tentacles. They had great agility and grace, and reflexes superior to those of a human.

Because of their ability to rearrange their cellular structures at will, thus taking on the shapes of various humanoid species,they are looked upon them with suspicion by other species. While Vendorians may assume many shapes and identities, the longer they remain in one form the more characteristics of that form they assume as  they can absorb memories and personality traits of an individual through touch. These memories and traits become more ingrained the longer or more frequently the Vendorian assumes the form; if maintained long enough, the absorbed traits eventually become part of the Vendorian's own personality. 

In the 23rd century, due to their practice of deciet as a way of life , they have been judged psychologically unfit for the interstellar communicty. Their planet has been quarantined to avoid them inflitrating other worlds and spreading chaos.

Source: Star Trek Universe ("The Survivor")

URSINOIDS

The Ursinoids are a sentient bear-like humanoids species which had devleoped spare faring as of the 23rd century. They have large fangs and were completely covered in fur. 

Note: They are reminsicent of the Bulrathi of  Masters of Orion

Source: Star Trek Universe ((TAS: "Mudd's Passion"))

TRAVIST POLONGS / POLONGANS

Planet of Origin: Polongus

Travist Polong are a species of small, sentient slug-like, multi-eyed beings. Some are known to have come to Earth at some point in the early 2010ies.

Source: Doctor Who Universe . (SJA: The Wedding of Sarah Jane Smith)  (SJA: The Mark of the Berserker)

GORGON

Planet of Origin: Gorgos ((100,000,000 light years from Earth)

The Gorgons were a species of intelligent parasitic beings which possessed their hosts. Non corporeal, individuals look like a group of blue ethereal serpentine forms hovering in the air. They had some psychic powers, specifically mind control and the ability to petrify creatures within a matter of hours. In order to do so, it needs to leave its host and make contact with the target. They can be reflected by a mirror, causing them to return to the host and turning it to stone. While in the host, they greatly increased its lifespan, letting one human host live for over 200 years. This was much less than the Gorgon's natural lifespan of thousands of years, which meant they had to frequently switch hosts.

Three Gorgons came to Earth around 1000 BC via a talisman, entering into Greek mythology along the way. One Gorgon was slain by a Greek hero, another by a professor and his wife in 1959, and one survived up til 2010. This Gorgon eventually inhabited the body of an abbess and led the sisterhood of nuns at St. Agnes Abbey, manipulating their minds to serve it for over 200 years. The Gorgon led the nuns on a mission to retrieve the talisman so as to call the Gorgons from their home world to invade Earth and take all of humanity for their hosts.

Source: Doctor Who Universe (SJA: Eye of the Gorgon)

EKNODINE

The Eknodine are a symbiotic sentient alien species that can live inside of specimens of other species, extending their lifespan. As a defense mechanicsm, they can extend a green eyestalk from their hosts' mouth, which can spray a green cloud which turn a human-size hostile into dust.
Note: There are similarities between this species and the Goa_Uld. and the Hive/Ganglion.
Source: Doctor Who Universe (DW: Amy's Choice)

TENZA

The Tenza is a species whose young were raised by other species. To that end, they possessed advanced, though subconscious, psychic powers, allowing them to live among the alien culture in which they were being raised. They born in space, where they drift until they found a habitable world. There, they find a family to live with, then infiltrate it. The Tenza infant would adapt itself to suit its environment and alter the memories of its surrogate parents and those around them. After that, the Tenza would live out its life as a member of the surrogate parents' species without conscious realization of its true nature.  If the Tenza felt threatened, its telepathic abilities played havoc with its environment to keep it safe.  They used a perception filter to remove inconsistencies in their histories. Their telepathic abilities are known to be able to scan space over distances of millions of light years.

Source: Doctor Who Universe (DW: Night Terrors)

BAJORANS / PROPHETS / PAH WRAITHS

Planet of Origin: Bajor, the 7th planet orbiting the star Bajor-B'hava'el, an earth type planet with five moons. A Day on Bajor has 26 hours. Bajor's atmosphere has a greenish tint; as a result, oceans viewed from space will appear more green than blue.

The Bajorans are a pacific  humanoid species who developed advanced civilisation about 500 000 years ago and started space faring in the 16th century. They were invaded in 2328 by the Cardassian Union, with who they had aligned themselves some time before. They were occupied for 40 years, during which time many Bajorans were forced into slave labor. Many fled and hid in refugee camps while other got involved in the terrorist resistance movement. In 2369, the Cardassian civilian authorities ordered the military to withdraw from Bajor, after which the Bajoran provisional government invited the United Federation of Planets to set up base in the system and requested membership into the Federation. Soon after, a stable wormhole was discovered in the system, making it a strategic position on the galacitc scale and a key entry point for the Dominion, an invasive civilisation lying at the other end of the Wormhole. Bajor finally formally joined the Federation in 2376, the year after the Dominion War ended.

The Bajoran people were originally divided into castes, called d'jaras. When the Occupation began, the d'jara system was abolished.

The Bajoran religion, known as the Way of the Prophets, is the major unifying force on the planet. Its religious figures are entities refered to as The Prophets, or "Wormhole Aliens" which, also they claim to be of Bajor, exist within the system's wormhole, referred to as the Celestial Temple by the Bajoran people. Their motives remain unclear; on several occasions they proclaim their disinterest in the physical world, while at other times actively participate in the physical world, most often in the general interest of Bajor and its people. People who followed the will of the Prophets are said to be permitted to enter the Celestial Temple and dwell with the Prophets upon their death. The Prophets are also believed to have given Bajor its main religious artifcacts, were discovered 10 000 years ago, the "Tears of the Prophets", crystalline, hour-glass shaped orbs , glowing and  floating within their containers and have powers defying scientific explanations, the most common being to stimulate visions that are beleived to communications from the Prophets. Some prophets, known as Pah Wraiths, are said to have been imprisoned by their kin on Bajor in a physical prsion known as the Caves of Fire for having tried to seiz control of the Celestial Temple in the past.

Source: Star Trek Universe

ASGARD

Planet of Origin: Unknown, in the galaxy of Ida
The Asgard are diminutive humanoid species which developed a benevolent highly advanced space-faring civilisation governed by a Hihg Council.  They were once part of an alliance of four great races with the Ancients, Nox, and Furlings and visited Earth during antiquity and protected a number of planets in the Milky Way, mianly from the Goa'uld with whom they signed The Protected Planets Treaty is an armistice between the Goa'uld and the Asgard, first referred to specifically in "Fair Game" when Earth is included. The treaty covers 27 planets including Earth,^[6] and ensures that those planets remain free from Goa'uld domination. Other planets in the treaty include Cimmeria,^[1] K'Tau,^[11] PX3-595,^[13] the second planet of the Adara system,^[3] and Galar.^[14] . As of the 20th century, the Asgard are a dying race. Having lost the capacity for sexual reproduction, they perpetuate themselves by transferring their minds into successive cloned bodies, leading to an irreversible degeneration of their genome. They chose to commit mass suicide in the beginning of the 21st century, having arrived at the end of their degenerative cycle, by exploding thri homeworld to prevent that their knowledge fell into the wrong hands.
A renegade faction of Asgard splintered from the others 10,000 years ago over their belief that they should experiment on humans to solve their cloning problems. They traveled to the Pegasus galaxy and continued their experiments, but were forced into hiding after the Wraith defeated the Ancients. 
Amongst the most significant technological advancements of the Asgard are beaming technology, intergalactic hyperdrives, advanced shiled technology and plasma beam weapons. They are very advanced in cloning techniques and have the technology to upload and store consciousnesses and transfer them to new bodies. Neutronium is a key element of Asgard technology. Source: Stargate Universe

AMNION

Amnion is an adavnced space-faring vaguely humanoid species which looks like " "a humanoid sea-anemone with too many arms." They differ greatly in appearance from one another, with differing numbers of limbs, eyes, and other organs, as well as  in size and shape. While being physically very different, they share a hive mind with the major instinctive drive of the expansion and propagation of the Amnion species, leading them to assmiliate other species by turning them into members of their own.

They possess  mutagenic technology that gives them the ability to rewrite the DNA of a non-Amnioni to turn him into an at least partially Amnion. Basic life processes remain intact, but protein and DNA structure are radically different. The new mutants can breed with each other (though not with mutated members of other species) and display a significantly increased level of intelligence.

First contact was made betwwen them and humanity while humanity was already travelling interstellar journeys.
Source: Stephen R. Donaldson's The Gap Cycle

GREATEST AMERICAN HERO ALIENS

Planet of Origin: Unknown, formerly a garden planet, now a wasteland. Its name is unpronouncable by humans.

The alien seen in The Greatest American Hero is from a green skinned humanoid species that developed an advanced technological civilisation. They had use of spacecrafts, teleportation and suits enabling their wearer to use flight, super strength, resistance to injury (including direct bullet hits to areas covered by the suit), invisibility, precognition, telekinesis, x-ray vision, super speed, pyrokinesis, holographic vision, shrinking, psychometry, and sensitivity to the supernatural.

According to the alien, his planet (which now looks remarkably like Mars) used to be a garden planet but is now a wasteland. He is therefore, as of 1983, among its rare survivors. He came to Earth to give a human one of their suits with which he hopes humanity will be saved.

Possibly coming from the same planet as him is a small creature floating in the air which ressembles a small snake with a torso, two arms a vaguely humanoid head on which is a long articulated antenna.
Source: The Greatest American Hero Tv show, ABC, 1981-1983

GAMILAS

Gamilas are a hibe-minded bipedal species which developed an advanced space faring civilisation.Knowning their planet doomed, they tried to invade Earth around 2199 and eradicate humankind. This decision caused a split of the hive personnality, one portion of it being against destroying another species. It sent technological information to Earth that would allow the humans to defend themselves. The Gamilas were eradicated.

Source: Space Battleship Yamato live action.

SLENDERS

Slenders are a species of tall circa 4 meters tall grey humanoids who developed an advanced space faring civilisation. They are an intrusive species, harnessing other species such as  skitters  and humans to control them and armed Mech drones to ensure their security. Graceful and slender, they can move very quickly in an Earht type gravity and appear to have features ressembling cetacean mammals. They are the apparent power behind the invasion of Earth. 

Source: Falling Skies

IXTL

Planet of Origin: Unknown but presumably destroyed for a long time.
Ixtls are a very ancient sentient species, thought to be extinct, although some specimen could still be floating in the emptiness of space in a state of suspended animation. They are red colored, with four legs and four arms ending in eight fingers. Their cylindrical body is virtually immortal and they have in full control of its  molecular structure, enabling them to survive unprotected in space for eaons in suspended animation and allowing them to withstand very high energetic discharges. To reproduce, Ixtl need what they call a Guul, i.e.living hosts in which it deposits their eggs. The eggs need only a few hours to hatch and then feed their living host.
Source: A.E. Van Vogh, The voyage of the Space Beagle

ASGARDIANS

Planet of Origin: Unknown but their current place of residence is Asgard, a place situated in a wormhole network (of which Earth is part) englobing 9 worlds. Asgardians have developed the Bifrost technology enabling them to teleport themselves instantaneously to any of the 9 worlds using the subspace network of the wormhole.

Asgardians are a highly advanced humanoid species. Earth'sNorsemen and Germanic tribes used to worship the Asgardians nearly a millennium ago. Even though certain Gods are still interested in humanity such as Thor, the Asgardians do not have any more active worshippers or seek to have any. Asgardian flesh and bone is about three times denser than similar human tissue, contributing to the Asgardians superhuman strength and weight. An average male god can lift up to 30 tons while an average female can lift up to 25 tons, but there are those that exceed these specifications. They  are also gifted with extremely long life, but are not immortal. They are also immune to all terrestrial diseases and are highly resistant to conventional forms of injury. The metabolism of the Asgardians gives them superhuman endurance in all physical activities. Their close genetic and morphologic resemblance with humans leads to believe that those two species, along with the other ones of the the 9 realms could be of a same origin.

Asgardians residing on theworld of Vanaheim are refered to as Vanir while the ones residing in Asgard itself are refered to as Aesir.

The other species of the 9 realms are:

• The Dwarves: Dwarves are small and stocky with an average height of 4 feet. Dwarves live in Nidavellir and maintain peaceful relations with the Gods. They tend to be either craftsmen or farmers and have created weapons for use by the Gods such as Mjolnir and the spear, Gungnir.
  
  
• The Elves: The two types of elves that inhabit the land are the Light Elves and the Dark Elves. The Light Elves live in Alfheim while the Dark Elves live underground in Svartalfheim. Both species are similar in the respect that their body types can differ greatly in size anywhere from 4 feet to 8 feet, and have proportionally long limbs. Light Elves have lighter skin tones while Dark Elves are darker.
  
  
• The Demons lives in the realm of Muspelheim. Demons are similar in size to the Gods, but are engulfed in fire. They tend to be nomads but will travel into other dimensions for the purpose of war. All Demons are the offspring of the fire demon who is said to be older than asgaridn culture, Surtur.
  
  
• The Giants: the Giants live on Jotunheim. They are also humanoid, but are more Neanderthal-like in body structure. They are the traditional enemies of the asgardians with whom they fought a millenia-long war that ended in 965 after they tried to settle on Earth. They were repelled to their homeworld, which was devastated and left without means to travel using the Bifrost network. Most stand up to 20 feet tall, but some can reach 30 feet. Giants usually lead a hunter/gatherer type of life, but will war with the asgardians on occasion because they are jealous of their superior abilities. The first of the Giants was the Ice Giant, Ymir, who existed before any of the Asgardians. Many different races of Giants arose in Jotunheim, including the Ice, Mountain, Rime, Storm, and Frost Giants. The Frost Giants are the direct descendants of Ymir. The Giant Laufey was another monarch who lost the war  against the Asgardians; In tribute to Laufey's courage and to try to seal a peace treaty with tthe giants, the asgardian king Odin adopted the giant's infant son Loki. Two other giants of note were Fafnir II and Fasolt (both deceased), who built Odin's palace in Valhalla in exchange for a Goddess, and battled over a magic ring and treasure that was given for the Goddess being released. Giants have also been known to reproduce half-breeds that look like asgardians.
  
  
• The Trolls: Trolls are massive creatures covered in hair with an orange skin tone. They average in at 7 feet, and they live in settlements scattered throughout the land. The trolls are incredibly strong, surpassing the strength of the asgardians, and puts them on similar ground with the Giants.Thor. Trolls usually work as miners and metal workers.

Sources: Thor movie, Marvel Universe, More on Marvel.com: http://marvel.com/universe/Asgardians#ixzz1S2qPajjt

SKITTERS

Skitters, are an aggressive space faring species of six-legged reptilian clawed insectoid aliens with two prehensile arms. They are nocturnal, speak in a kind of strange language with a manbidle equipped mouth and possess light-green eyes with vertical black pupils. They appear to have armor that covers their body except for their head and legs. They invaded the Earth in the early 21st century and destroyed all major cities. At first they were not engaged because humanity thought they might be peaceful. They "harness" children using a centipede-like parasite to control the children's minds so they can communicate with humans. They use bipedal Mechs and airships. 

Source: Falling Skies series 

BATTLE LOS ANGELES ALIENS / BLAA

Planet of Origin: Unknown. Given the decrepit appearance of their ships and equipment, it's possible that the aliens that come to Earth in 2011 may not be part of the dominant force in their homeland and may be looking for a new home planet, possibly due to their old home being uninhabitable because of warfare or some other cataclysm. This would explain their War of the Worlds-esque landing method, as well as their relatively low level of technological advancement for a spacefaring civilization. It is theorized  that they are invading for Earth's liquid water.

Description: The Battle: Los Angeles Aliens (often refered to as Blaa) are an aggressive advanced spacefaring caste-based bipedal carbone-based organic species practicing heavy cybertransplant on themselves.They are divided in castes, easily recognisable by their morphological specificities and the nature of their implants. 

Four warrior castes are known to exist.The warriors are highly developed bipeds with four fingers hands among which are opposable thumbs. They sport redundant arteries and other blood vessels. Their heads are actually entirely sensory organs. Their brains are located in a cavity behind their hearts, directly attached to the spine. They have large numbers of stem cells and platelets, enabling them to regenerate whole limbs that may be lost in combat, while their hardened exoskeleton allows them to take heavy damage before being too injured to continue fighting. All warriors have substantial amounts of machinery implanted into their bodies, including communication, cooling, and weapons systems. Their perception is also very acute, supplementing their precognitive and retrocognitive abilities. 

Infantry Caste: The Infantry Caste can be identified by weapons grafted onto each arm where grasping hands would be. Their average height is about 8'1". While they are taller than humans, they are proportionately thinner. All of their vital organs are concentrated behind layers of muscle and arteries in the right of their chests. A cooling system is also integrated into their body, with a heat-dispersing fan located in front of their organs. Unlike many of the other castes, they do not have as much machinery located on their back.

Officer Caste: The Officer Caste is the easiest caste to differentiate from the rest, identifiable by their slender build and four mechanical legs replacing their biological ones, which enable them to move at speeds of up to 40kph/24.8mph with relative ease. They are also the tallest caste with an average height of 9'4". The Officers are specialized in commanding groups of infantry, augmented by an unusually large, well-developed brain and very keen eyesight which has been supplemented with additional electronics. The Officer caste have the most substantial amount of cybernetic enhancements. As their legs have been wholly replaced, they are able . Their right arm has an implanted weapons system that trades firepower for accuracy, while their left grasping hand has been replaced by a mechanical claw. 

Operations Caste: The Operations Caste share many similarities with the General Infantry Caste, with a few notable exceptions. The Operations average about 6'11". The special forces appear to be a more intelligent Infantry soldier, expected to undertake specialized goals beyond that of simple shock troops. They also appear to be a middling caste, lacking the firepower of the Infantry and the intelligence of the Officer. Unlike the officer and infantry castes, the Operations have retained their left grasping hand and are able to make use of hand signals. Their weapons systems sport greater accuracy than those of the general infantry, but a less-powerful grenade launcher.

Intelligence Caste: The Intelligence Caste is likely specialized in their namesake, gathering information and laying down lines of communication. Averaging about 5'10", the Intelligence caste are the shortest and stockiest of all known warrior castes. Unlike all other warrior castes, the Intelligence Caste lacks any integrated weapons systems. However, they retain the large amount of cooling and communications machinery grafted to their backs. The lack of weaponry is made up for by their ability to utilize both grasping hands, which they use to operate machinery and vehicles, such as driving ground artillery platforms and operating walking guns. 

Water Extractot

The full extent of their space-faring capabilities is not known. Most of their light weaponry uses projectiles, but they also use heavy energy weaponry. Although the known vehicles make use of different forms of propulsion, such as walkers and hovercrafts, none are wheeled. All are oriented toward greater mobility, at the cost of armor and therfore, the protection of the users. The have intensive use of cybernetic implants and replacement of actual body parts and do some genetic engineering to increase efficiency of castes,An extreme case of such engineering is the Water Extractor, a specialized alien, used as biological pump that is used to move massive amounts of water quickly, growing as large as 100 feet in height. The Extractor's organs have been greatly reduced and compacted, leaving only organs that are vital to life functions. Extractors are highly intelligent and use an advanced form of communication to coordinate their actions for maximum efficiency. The extractors are deployed along with the initial invasion force, landing off-shore and using modified tentacles to quickly pull water from the surrounding environment. 

The aliens  launched a surprise invasion on Earth, most likely motivated by a need for a new home or colony on the 12th of August, 2011. Originally mistaken by the Humans to be clusters of meteors, their  spacecraft landed off the coastal shorelines of twelve of the world's major population centers. Their ground forces subsequently attack many of Earth's major cities, including Paris, London, Moscow, New York, Hong Kong, Rio de Janeiro, and Tokyo. Their aircrafts eventually arrive and appear to easily take control of the air above the cities  from the human Air Force. Besides their ground and large air forces, they deployed a sort of command center controlling unmanned flying drones. In Los Angeles, within a few days, the drones  pushed most of the U.S. military force out of the city, killing thousands during the engagements but a squad of Marines  able to destroy the command center, disabling all of the drones and depriving them of their air assets. These Marines later retreat back to a command post, and join up with thousands of reinforcements ready to try and take back Los Angeles from the invaders. 

Souce: Battle Los Angeles, Battle Los Angeles wiki

ALIEN PICTURE OF THE DAY

BLOWFISH

The Blowfish  a species of piscene humanoids with a face strongly resembling a earth blowfish and sometimes refered to as Homoformatus piscis. They have bright red skin, a large crest on their head and tendrils and feelers around their face. Next to the jaws are gill slits, with the sensitive gills inside. They can breath both water and air and are revitalised with water. They have stinging, yellow sputum. They like to eat  algae and are susceptible to electrical shocks than humans.

They had developed an advanced space faring hedonist civilisation as of 102 A.D. and had contact with other spacefaring civilisations.

Source: Doctor Who Universe (TW: Kiss Kiss, Bang Bang, Fragments) (DW: The Pandorica Opens, The Big Bang)

NOVARIANS

Planet of Origin: Nova, a planet orbiting a star of the Milky Way

The Novarians are species of large hairy simians which have developed an advanced space faring society. A novarian expedition crashlanded on Earth around the beginning of the twentieht century while they were on a survey mission. They have been stranded on Earth ever since. Their large hairy appearance gave rise to the legend we know as Bigfoot. Sometime in 1980, a group of earthbound heroes nicknamed the SuperFriends helped them repair their ship and get back to their home planet

Source: (DC Universe non canon) Superfriends, 1980 Shorts: Bigfoot

PYTHO-REXIANS

The Pytho-Rexians are a subterranean species living on the planet Venus' Underground. Standing a bit less than two meters, they have tentacular limbs attached to a small body and a head with two large yellow eyes and one featureless mouth. They have a theocratic society based on the worship an idol statue called Pytho-Rex. They are ruled by a religious leader called the Elder who is supposedly able to communicate with the statue, claiming that everything that he commands is the will of Pytho-Rex but no scientific proof has been made to confirm this assertion. They possess some level of technology allowing them to have built beam weapons.

Source: DC Universe (non canon) The Superman/Aquaman Hour of Adventure (1967-1968), A Visit to Venus

FEARIANS

The Fearians are a species which had developed space travel as of the twentieth century. They stand about two meters tall, with a light-blue skin humanoid body on top of which are three pointy heads. They tried in vain to invade Earth circa 1978 with the help of a super-powered terrorist group. They were at the time claiming to come from Venus.

Source: (DC Universe - Not Canon) Challenge of the Superfriends, Season 3 (1978), Invasion of the Fearians

UN Z'BRI MELANIS DE TRIBE 8

Z'Bri Melanis from the universe of Tribe 8 published by Dream Pod 9.

KRILLITANES

The Krillitanes are a metamorphic carnivorous species with very sensitive earing that can take physical features from other species. Circa 1100 BC, they looked like humanoids with long necks and hooked tails. After having invaded planet Bessan, they started to growbatlike wings like Bessans. Some came to Earth around this time. A small group was also present around 2007.

Source: Doctor Who Universe: School Reunion, NSA: The Krillitane Storm

THE SILENCE

The Silence are humanoids ressembling grey aliens. They stand nearly 2 meters tall with bulbous heads and grey, mouthless faces. Their hands possessed large, elongated fingers with a bulbous central finger. They speak in low, guttural voices and tended to make growling or clicking noises. Their bodies are covered with what appears to be black suites. As soon as someone is not looking at a Silence, its memories of it blanks out of his memory but remains in his unconscious as upon looking on a Slience again, previous memories of meetings come bac (also to blank out as soon as visual contact is lost). They absorb energy from nearby energy sources and discharge it from their hands with enough power to disintegrate a human. When absorbing the energy and discharging it, a hole appeared where a mouth should have been. They can influence humans by saying something while a person was looking at them, which would remain in there heads after they looked away in a form of post-hypnotic surgesion. Constantly doing this would cause the person in question to lose their mind.
The Silence were apparently present on Earth for hundreds of years since the time the wheel and fire were developed, going unnoticed by the human race. The Silence were defeated by the Doctor when he ensured humanity saw footage of a Silent ordering people to kill them on sight, broadcasted via the moon landing. This 'command' acted like a post-hypnotic suggestion and resulted in the human race finally turning on the Silence.
Source:Doctor WHo Universe : The Impossible Astronaut, Day of the Moon

SKYLINE ALIENS

The aliens travel through space, visiting planets on which they project sort of blue energy that connect them all as lure which mesmerizes indigenous lifeforms. The victims are then harvested before their central nervous system is extracted to be used, it seems, as power source. The aliens are divided in several specialised subspecies, some of which have been witnessed.

The largest known entity is the Mother Ships which comes in all shapes and size but is usually several hundred meters long and able to travel interstellar distances, transporting the smaller specimens of the species. They seem to be moving in pack from worlds to worlds.

The Tankers are anthropomorph entities 20 to 30 meters tall. They are used as cleanup crew, gathering the indigenous specimens that have escaped being lured by the blue light.

The Hydras are the big flying squid creatures.

The drones are smaller octopus creature, which are able to enter tighter spaces.

There seems to also be smaller anthropomorph aliens which stays inside the mothersip and most likely others which have not been witnessed yet.

Source: Skyline