Vocal cord parasite

The vocal cord parasites were a group of parasitic organisms that infested the victims' vocal cords.

History
The parasites were discovered by Code Talker upon researching the remains of The End after Operation Snake Eater in 1964, and later reviewing the records of The Pain as well, although he had theorized their existence as early as the 1930s. After studying the parasites and even allowing The End's parasite to assimilate with his own body, Code Talker had the parasites sealed away. The American Philosophers found Code Talker's research and attempted to recreate the parasites as part of the cleanser project, but the project was abandoned after targeting an entire language was deemed too inaccurate to be useful. The parasites were later resurrected in 1975 through reverse evolution. Unfortunately, they were uncovered and stolen by Skull Face who forced Code Talker to work for him in making other strains until he was rescued by Venom Snake of Diamond Dogs. Skull Face himself was infected with every strand of the parasites except for the English version, which also cost him his ability to speak his native tongue, Hungarian. He also used one of the English strains of the parasite on Zero in order to confine him to a persistent vegetative state rather than kill him outright.

The parasites were used in the creation of the Parasite Unit and the return of Quiet to active service. He also attempted to use them in his plans in the 1980s, alongside metallic archaea and the Sahelanthropus, to wipe the English language and vocal lingua franca off the face of the Earth, although he had earlier led Code Talker to believe that he planned to use the vocal cord parasites to act as an ethnic cleanser to wipe out all languages except for English from the face of the Earth. In his final battle with Venom Snake, the latter destroyed one sample of the English strain. However, Tretij Rebenok managed to take the remaining sample before it hit the ground after it was thrown by Venom Snake. This was unnoticed by him and Kazuhira Miller. This sample was later supplied to Eli by Tretij Rebenok in secret shortly after returning to Mother Base. Before his death, Skull Face, when Venom Snake attempted to inquire where the third sample was due to it being missing, cryptically stated that it was very close to him.

Two outbreaks of the parasite in its contagious form occurred on Mother Base. The first spread amongst speakers of Kikongo and was only halted after Snake rescued Code Talker from XOF forces. Code Talker revealed that Wolbachia bacteria would cause the parasites to mutate all of the male parasites into females, halting any chance at the parasites reproducing and causing more symptoms, but at the cost of the fertility of all those innoculated. He also revealed that children act as carriers of the parasite, as the parasites only infect matured vocal chords, and the war orphans' rescues to Mother Base were the reason that the Kikongo parasite infection occurred. It is also revealed that Snake's destruction of the Mfinda Oilfield was what caused the Kikongo infection to spread, as Skull Face had intended to pollute the water to contain the parasite infection he had tested elsewhere in the Angola-Zaire border region. The second outbreak was caused as a result of Huey Emmerich mutating both the parasite and the Wolbachia with beta radiation. The Wolbachia mutation changed the female parasites to undergo parthenogenesis, a form of asexual reproduction, leading them to reproduce more female parasites for the Wolbachia to infest. The parasites mutated as well, making the infected staff members smell sickly sweet and infected them like how the Leucochloridium worm parasitizes snails, driving the men mad, not unlike what happens when humans are infected with toxoplasmosis, to get to the top roof of the quarantine platform where the circling crows, drawn by the sweet smell, would peck at them and then spread the infection to the whole world. Venom Snake prevents the worldwide outbreak by killing the infected in the quarantine platform, even though some get by him at first and get incinernated by a napalm bombing on the roof, using specially modified night vision goggles that detect the parasites in the infected victims' throats. The remaining fallen are cremated to neutralize the parasite, and then their ashes are compressed into diamonds to be held by the Diamond Dogs as they go out into battle. Huey is identified as the traitor after it is revealed Mother Base had been monitoring his transmissions (and all transmissions sent out of Mother Base) to sell the parasite to DARPA, which was connected to Cipher, in exchange for safety. Huey is exiled as a result, still trying to pin the blame on Snake for having killed the men, despite it being his fault at first.

After Eli had been discovered to be behind the orphans' escapes off of Mother Base, he and Tretij Rebenok escaped Mother Base with some of the other children and Sahelanthropus. They made their base on an island in a salt lake in central Africa, infecting the entire island with the parasite and killing off all adults. He only avoids being infected himself because he is still a child, and he keeps a gas mask on at all times. However, as time goes on, his voice begins to crack, hinting that he will soon become a victim and vector of the parasite as well. Snake infiltrates his island, while Cipher forces invade as well to try to recapture Sahelanthropus, and after a battle Snake downs the Sahelanthropus while Eli pilots it. With Sahelanthropus down, Cipher forces approach Eli and Snake, and a flash grenade is fired, leading Snake to suffer a seizure that makes him colorblind to the color red, the same color as the jumpsuit Eli was wearing while piloting Sahelanthropus. Snake shoots the masked Cipher soldiers going to kill him and Eli, but shoots Eli as well, just as his color vision returns to normal. Diamond Dogs forces arrive on the island to extract Snake and treat Eli, who is revealed to be wearing a bulletproof vest, but a medic discovers Eli has been infected with the parasite as well. Diamond Dogs leave Eli to his fate, with Snake even giving him a gun to kill himself before the parasite takes hold, but Tretij appears, stopping him, and using his telekinetic powers to remove the parasite from Eli's body, and he takes him off of the island before Diamond Dogs' napalm carpet bombing eradicates all life on the island to prevent the parasite from spreading again.

Zero himself hinted that the original project of the American Philosophers to use the parasites would eventually evolve into the FOXDIE virus project, allowing the Patriots to target the victim's genetic code itself rather than just their language.

Capabilities
Initially in larval form, the parasite entered through the throat and attached to the vocal cords, mimicking the host's membranes flawlessly. Upon reaching maturity, the larvae mate, triggered by sustained exposure to the specific language the parasite was attuned to, though parasites could be scientifically manipulated to target specific languages, as Skull Face attempted to use them to eradicate English as a language by having the parasites kill all who spoke it. The resulting larvae then feast on the host's lungs, killing the host. As the hosts die, they revert to a zombie like state of dementia that violently work to ensure the parasite infects others and spreads throughout populated areas. The zombie like infected only want to carry out the will of the parasite controlling them and lose their own willpower, sense of loyalty, and sanity upon their succumbing to the parasite's control. Once symptoms of infection manifest, the larvae had infested the host's alveoli, at which point nothing could be done to save the host.

Code Talker possessed a pipe with an herb that the parasite disliked, which, when smoked, would allow the host to speak for some time with their parasite "deafened." He also possessed a strain of the bacteria genus Wolbachia that could, by turning the male version of the parasite to females, halt the onset of symptoms, but would also make the host infertile. In addition, contamination of water will also prevent infection, as XOF, via the front company SANR, caused an oil leak to ensure the parasite cannot be spread to the local villages as the area the oil facility was at contained mass graves of people infected with the parasites.

"The One That Covers"
A similar parasite to the vocal cord parasite, albeit one that was deliberately said to be different, was known as "the one that covers." This parasite was provided to the Parasite Unit and, in a mutated strain, to Quiet. Some hosts generated a pitch black gas that could sometimes sparkle blue. The parasite acted as the host's skin, to a variety of effects. A primary effect was providing camouflaging abilities to the point of invisibility, phasing layers of flesh in and out of the visible spectrum to the point where the muscular system was sometimes visible. The black gas appeared when the subject vanished into thin air with their powers. Other possible abilities included disguising as another military force, and reinforcing the skin to a kind of armor. The armor and mist variants of the Skulls could even produce their sparkling black gas and make their victims zombie like infected that worked with them to achieve their goal. This meant that these varients could turn others into violent zombies like those infected with the normal variant. Inhuman mobility, strength and resilience are highly common amongst these kinds of subjects. In addition, weaponized subjects could float down while mid air and slow their falls. In return, the parasite took in "nourishment" of some sort.

The parasite could also replace lost organs of the host, as seen in Quiet's and Code Talker's replacement of their digestive systems to make them photosynthetic, as well as the modification of her respiratory system to be cutaneous (through the skin) rather than pulmonary (through the lungs). Quiet was also ressusitated near instantaneously by sunlight alone after being drowned. The End had similar abilities, causing him to rapidly heal in sunlight, have inhuman resilience, and survive exposure and from lack of shelter as long as he was exposed to the sun, air and water.

Strains
Some of the vocal cord parasites bestowed special abilities upon their hosts if compatible, especially the weaponized variant known as "The One That Covers." It was never fully explained what the difference between the parasites that caused death and the parasites with superhuman attributes was. It was also never determined what their full potential for abilities was, but several different kinds have been identified.
 * Expanding natural human lifespan to approximately one-hundred years
 * Replacing and replicating the processes of the organs of the digestive system
 * Superhuman strength, speed, and agility ("The One That Covers")
 * Storing synthetic materials inside of the skin, such as firearms or metallic archaea ("The One That Covers")
 * Near-invisible camouflage by augmenting pigments in the skin ("The One That Covers")
 * Converting the skin into a black rock-like material as armor ("The One That Covers")
 * Limited telekinesis ("The One That Covers")
 * Photosynthetic skin ("The One That Covers")
 * Dispersal of a mist to obscure sight ("The One That Covers")
 * Releasing heterogeneous pheromones that attract insects
 * Releasing high amounts of adrenaline to override pain
 * Keeping the host alive long after their death by feeding off of anger and rage

Behind the scenes
The parasites are a major element in Metal Gear Solid V: The Phantom Pain. In one of the cassette tapes, it is revealed that, in addition to The End's parasite, The Pain had parasites as well. The End's parasite would later be transferred into Code Talker.

"Mist Parasite Parasites extracted from Mist-type Skulls. They possess the ability to produce a dense mist. Required for developing and using parasite supply cartridges."

- Mist Parasite description in Metal Gear Solid V: The Phantom Pain

"Camo Parasite Parasites extracted from Camo-type Skulls. Required for developing and using supply cartridges."

- Camo Parasite description in Metal Gear Solid V: The Phantom Pain

"Armor Parasite Parasites extracted from Armor-type Skulls. They possess the ability to protect their host's body through calcification. Required for developing and using parasite supply cartridges."

- Armor Parasite description in Metal Gear Solid V: The Phantom Pain

The parasite bears a resemblance to an unnamed virus featured in the book-turned-movie Pontypool Changes Everything, which is transmitted via the use of English vocabulary and causes zombie-like behavior in its host.

Appearances

 * Metal Gear Solid V: The Phantom Pain