BYNARS

Planet of Origin: Bynaus, a planet oribiting the star Beta Magellan, in the Milkty Way galaxy within a 1000 light years of Earth.

The Bynars are a species os short genderless sentient humanoids with lilac skin and enlarged skulls. They have a patch of dark purple hair on both sides of their neck and asymmetrical ears. They work and live in pairs, usually with a matching asymetries to equate to a symetry. Their primary language consists of high-frequency sounds, unintelligible to humans but they are able to change frequencies down to communicate with other species.

They developed a technologically advanced civilisation in such a way that at birth, each bynar's parietal lobe is surgically removed and replaced by a synaptic processor taht allows them to connect directly to a central master computer they built on their homeworld. Every Bynar is equipped with a buffer, carried at their waist, to help them manage the  rate of information they send and receive.

In 2364, due to a nearby star going nova, they were temporarily forced to shut down their computer which caused a planetwide black out.

Source: Star Trek universe, (TNG: "11001001"). (ENT: "Regeneration"), created by Robert Lewin and Maurice Hurley.

TELLERS

The Teller are large muscular sentient humanoids gifted with powerful telepathic powers. They have grey elephant-like skin and elephant-like feet, a vaguely snail-like head with articulated eye stalks on each side of it, a short ribbed tail and two long claws serving as hands. Their nostrils are presumably situated under in series, along their eye stalks. One of their main defense mechanism consist of emissions of psywaves that can liquify the brain of their victims, indicently causing the skull to cave in.

They probably developed a primitive culture on thier howeworld but were all exterminated after being discovered by offworlders, presumably humans, at some point in the future. Two were kept alive to serve as guilt detectors for a galactic bank until the bank was closed and they were relocated to an uninhabited world.

Source: Doctor Who universe, Time Heist TV episode.

ZYKARIANS

Planet of Origin: Zykaria

Zykarians are two species living in symbiosis, one being looks much like a humanoid headless body, the other, much like a human head. The body by itslef seems to have limited initiative, most of the thinking for both being done by the head being, which in exchange, rely the body for locomotion, prehension, protection and sustainance. It is important to note that the head needs the help of the body to disengage itself from the ladder.

Zykarians have been known to ingest food by the mouth, which leads to believe that the head is a channel to get nutriments in the body who is in charge of digestion. If it is the only channel remains unknown.

No Zykarian females has been seen by members of other species and their existence in fact remains a big point of interrogation although, while the Zykarian reproductive cycle is unknown, it has been reported that some individulas have displayed some levels of attraction to females of other species such as humans.

Zykarians have developed an advanced technological space faring if somewhat secretive civilisation as of the 25th century with occasionnal contacts with Earth.

Source: Buck Rogers in the 25th century TV series, season 2,  Journey to Oasis

PROCESS

The Process is oviparous wormlike sentient annelid parasite looking much like a leech with lamprey-like mouths at each end. It moves by cartwheeling itself end over end, leaving a slime trail behind. It had clawed fins and red-brown skin which turned grey with age. It possesses some psychic powers and traps its victims in silk cocoon to  feed on their mental energy but also appears to be datavore, sustaining itself by consuming information.While originally not bigger than normal leeches, with enough food, it is able grow the several meters in lenght.
Its origin is unknown but one specimen is known to have been in Ealing, UK, during the 1990s, at which point it got on stow away in a time machine and disappeared from the planet.
Source: Doctor Who  universe, Cat's Cradle: Time's Crucible.

POD PEOPLE / BODY SNATCHERS

The Pod People are a nomadic alien species of small gelatinous creatures originating from a dying planet. They evolved the ability to defy gravity and left their planet in search of a new world to settle on to float in space for millenia before occasionnally landing on suitable worlds. The Pods' sole purpose in life was that of individual survival, with no attention given to the civilizations they conquered or the resources they squandered. They would then consume all of the planet's resources, only to then leave in search of yet another new world. It is hinted that such a consumption was the fate of the civilizations that once inhabited Mars and the Moon. 

Upon landing on a planet, they would try to replace the dominant species by  growing into large plant form which would spawn emotionless replicas from its pods; As a pod reaches full development, it assimilates the physical characteristics, memories, and personalities of any sleeping person placed near it; these duplicates are devoid of all human emotion. The assmiliation process would leave the original bodies to disintegrate into dust once the duplication process was completed. The duplicates had lifespans of only five years, and could not sexually reproduce.

Earth was among the planets the landed on. Stories of case where such cases happened

In 1956, they landed in a small California town. Alien plant spores grow into large seed pods, each one capable of reproducing internally a duplicate replacement copy of each human. A local doctor uncovers what is occurring and managed to stop the invasion with the help of the Federal Authorities.

In the 1978 invasion, the pod landed in San Francisco and managed to bring their effort further. The replicas showed the ability to communicate thru scream in a creepy alien voice to alert other pod people of those not yet taken and seemed to exhibit a kind of extra-sensory perception. Replicas merging more than one subject were also witnessed like a case of a merged man and his dog.

As similar scenario happened in 1993 in an Alabama Amry base.

In 2007, the invaders changed their method, from pods, they made contact with humans directly through liquids and then worked much like viruses which,  once the person had fallen asleep,  rewrote human DNA. The aliens then vomited a gelatinous substance into liquids to help the invasion continue. When the invasion gains considerable strength, the pod people transform humans by directly injecting them with the substance, under the guise of "influenza vaccines".  However, it was discovered that people who had certain illnesses during childhood were completely immune to the virus. A vaccine was created and the entire pandemic is cured within a year; those infected, after being treated,we re unable to remember events during their infection, "as though they were in a deep sleep".  In one California town, though, the invaders used their traditional method, but with more egg-like pods.

Source: Jack Finney's  novel The Body Snatchers. (1954);

Invasion of the Body Snatchers (1956 film); Invasion of the Body Snatchers (1978 film); Body Snatchers (1993 film); The Invasion (2007); The invasion of the Pod People (2007)