Long One

The Long One is a parasitic alien organism that appears in the 2006 horror-comedy film Slither. Described as a "conscious disease", this life-form travels across the universe in search of life-forms to kill, infect and devour. It perpetuates this process on every inhabited planet it comes across, infecting the native beings of a given world, spreading and consuming all life until there is nothing left, after which it will move on to another world. The origins of the Long One are unknown as are its means of travel between planets, although in the film Slither it arrives on Earth in a meteor, presumably a fragment of the last planet it destroyed.

History
In the film Slither, the Long One arrives on Earth in 2006, landing near the small town of Wheelsy, Iowa. It emerges from the meteor which carried it in the form of a bulbous, gelatinous sac resembling a large maggot. It is discovered by the human Grant Grant and launches a small, needle-shaped protrusion into Grant's torso. The Needle burrows through Grant's body and into his brain, fusing with him and taking control.

As time passes, Grant follows the nature of the parasite, buying large amounts of meat and secretly killing neighbourhood pets, cattle and wild animals. He also visits Brenda Gutierrez at her home and rapes her, using his new mutant proboscis to turn her into a Womb. He then locks Brenda away in a barn out in the woods where he feeds her the raw meat he's been gathering. As time goes on, Grant becomes steadily less human, developing growths and lesions all over his body. Eventually, Grant's wife Starla catches on to his strange behaviour and witnesses his new mutant appendages protruding from his torso. Grant then flees into the woods.

Three days later, animals continue disappearing from the farms around Wheelsy and police chief Bill Pardy and Mayor Jack MacReady round up a posse to find Grant and the missing Brenda. During a stake-out, they find Grant out in a field dragging a cow into the woods. By this point, Grant no longer looks human, having turned into an amorphous blob of a creature with tentacles. The posse follow the mutant Grant into the woods and come across the barn where Brenda has been held. They go inside to find Brenda who has swollen to grotesque proportions as her body expands with thousands of small parasitic Slugs. Shortly after, Brenda is torn apart from the inside as her enormous clutch breaks free, swarming over the posse members and slithering towards town where they go about infecting the population. Bill, Starla and MacReady avoid being infected as they keep their mouths shut to keep the slugs from entering.

Meanwhile, Grant returns home where he makes his "nest". Guiding the Slug hosts telepathically as extensions of himself, he sets about infecting and/or consuming all life in town, adding multiple human bodies to his own biomass and growing like a sentient cancer, intent on growing and spreading until he covers the entire world.

Starla is captured by Grant's zombified slaves and brought home where Grant attempts to "set the mood" before making her a part of him. In a sense, Grant is still being governed by his emotions, most notably his love for Starla. Starla notices this and attempts to use it to her advantage, keeping Grant distracted while Bill Pardy and Kylie Strutemyer attempt to get close enough to kill him. With his multiple slaves acting as his eyes and ears, Grant notices what's happening. Bill tries to throw a grenade at Grant, but Grant slaps the grenade away with a tentacle and it explodes in his swimming pool. Grant then grabs Bill and attempts to turn him into a breeder, jabbing one of his proboscis tentacles into Bill's torso. Bill manages to grab the second proboscis and forces it into the ruptured nozzle of a propane tank. The volatile gas enters Grant's swollen body and Starla grabs Bill's gun, shooting a bloated area of Grant where the gas is collecting. The gunshot ignites the gas and Grant explodes in a shower of mutated meat. When Grant dies, all of the worms and infected townsfolk die as well.

Life Cycle
The Long One exists in many physical forms. Though it isn't explicitly mentioned, it can be categorized into four entities or forms, (at least, for the purposes of this discussion). These are the Needle, Primary Host, Womb and Slugs (see notes below).

Needle
The Needle is the original form of the Long One. It is called Needle, because of its resemblance to a needle, albeit much thicker and seemingly hairier. It is encased in a small gelatinous sac, which opens up when the Long One is ready to shoot out and implant itself into a host. Once implanted into a host, the Needle merges with the host and turns into the Primary Host.

The Needle is encased in a small gelatinous sac, probably as a defence mechanism for when it lands on a new planet like Earth, whose atmosphere is foreign to it. It can also be thought as a protective shield for the small fragile Needle form of the Long One. The sac opens up when a viable host comes nearby and the Needle shoots into its abdomen and travels to the brain. In the case of Grant Grant, the Needle shoots itself into Grant's breastbone, slithers up his brain stem and settles in the hind-brain region, initially taking control of his cerebellum and eventually (as suggested, though not mentioned) moves up to control his cerebrum. The cerebrum and cerebellum function together to control all voluntary muscles as well as aid in sensory, language and memory processing. This control becomes evident when it is observed that the Long One not only controls Grant's movements, but also shares in his memories and communication skills. It is also evident in how the Long One, across all its forms, functions on a "hive mind" mentality, which is why the Womb, the Slugs and all infected hosts function as a singular unit.

Primary Host
The Primary Host is a changing and growing form of the Long One. It starts out looking like its original host and is continually deformed to eventually resemble a giant squid over time. It is characterized by its whip-like tentacles emerging from various points of the Primary Host's body after full mutation. When the Needle implanted itself into Grant Grant, his physical appearance could be compared to a cross between a squid and John Carpenter's rendition of the Thing.

Since the Long One is a hive-minded being, the Primary Host therefore acts sort of like a home base, allowing it movement and speech, something that its original form as a Needle couldn't do. The Primary Host will start to develop rashes, swelling, and an insatiable hunger for any raw meat it can get, eventually growing tentacles and evolving into a grotesque monster. Its tentacles are strong and flexible enough to kill animals from a distance, which is important for the Long One as it feeds on raw meat. It is also strong enough to vertically split a human being. The Primary Host moves by slithering, despite its larger size; however it stops moving at some point when it feels it is no longer threatened or when it is too large to physically move due to merging with more hosts. The Primary Host does not lose total control however. This is evident in how the Long One still is longing for Starla, Grant's wife, which is indicative that Grant is still present in the decision-making process. It becomes more evident in how Grant is able to suppress the Long One from killing Starla.

Womb
The Long One also needs a Womb to give birth to Slugs, which in turn makes more Hosts. The Primary Host impregnates another host by injecting its material through two tentacles emerging from its body. In Grant's case, two tentacles extending from a hole in his abdomen act as the vehicle to transport the Slug eggs into Brenda's stomach. The impregnation requires two tentacles to penetrate the host's body, as one is not enough. The Womb can still think and speak with some semblance of rationality, but is distracted by an overwhelming desire to eat (signifying a control of the hosts hypothalamus), busying its time consuming raw meat. The eating allows for the birth of hundreds, maybe thousands of Slugs, which burst out ripping the Womb apart.

Slugs
Slugs - also called Worms - can be thought of as the worker-bees or extensions of the Long One, capable of infecting more hosts at once. Unlike the Needle, the Slug's control on a host is limited only to movement and communication. No cognitive or independent ability is ever manifested. Because of the hive mind nature of the Long One, Slug-controlled hosts have the same memories and exhibit the physical mannerisms as the Primary Host. The Slug-Hosts - also known erroneously as "worm-heads" - can spit an acid-like substance that causes a burning sensation and increased blood pressure of the affected area. The Slug-Hosts live for two purposes: To gather food for the new Wombs and to synthesize or merge with the Primary Host, allowing the Long One to become bigger over time and thus consume more.

It is possible to remove the Slug before it manages to completely enter the host however. This has only happened once with Kylie Strutemyer, who managed to fight the slug that was trying to enter her, long enough for it to weaken and allow her to pull it out of her mouth. This encounter also transferred some of the Hive's memory of other planets that have been previously consumed to Kylie, granting her knowledge of what was happening in Wheelsy.