Vocal cord parasite

The vocal cord parasites are a group of parasitic organisms that infest the victims' vocal cords.

History
The parasites were discovered by Code Talker, who had the parasites sealed away. Unfortunately, they were uncovered by and stolen by Skull Face by way of his infected Parasite Unit, who forced Code Talker to work for him in making other strains until he was rescued by Venom Snake of Diamond Dogs.

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. In his final battle with Venom Snake, the latter destroyed almost every sample of the English strain.

Two outbreaks of the parasite in its contagious form occurred on Mother Base. The first was halted by Code Talker providing the symptom-halting wolbachia, but the second, immune to the wolbachia, was only stopped when Venom Snake made his way through the quarantine zone, executing everyone who was infected.

Eli, with the final sample of the English strain of the parasite, infested an entire island, which had to be sanitized with napalm across its entirety. However, he himself kept a strain of the parasite inside him, and, symptomatic, he was nevertheless healed by having the parasite telekinetically removed by Tretij Rebenok.

Capabilities
Initially in larval form, the parasite enters through the throat and attaches to the vocal cords, mimicking the host's membranes flawlessly. Upon reaching maturity, the larvae mate, this copulation triggered by sustained exposure to a particular sound, that of a specific language's words, the language to which the parasite is attuned to. The resultant larvae then feast on the host's lungs, killing the host. Once symptoms of infection manifest, larvae have infested the host's alveoli, at which point nothing can be done to save the host.

Code Talker possessed a pipe with an herb that the parasite dislikes, 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.

The One That Covers
A similar parasite to the vocal cord parasite, albeit one that is deliberately said to be different, is known as "the one that covers". This parasite was provided to the Skulls, and, in a mutated strain, to Quiet. The parasite acts as the host's skin, to a variety of effects. These include reinforcing the skin to a kind of armor, providing camouflaging abilities to the point of invisibility or disguising as another military force, superhuman speed and jumping, and and superhuman strength. In return, the parasite takes in "nourishment" of some sort.

The parasite can also replace lost organs of the host, as seen in Quiet's replacement of her digestive systems well as the modification of her respiratory system to be cutaneous (through the skin) rather than pulmonary (through the lungs).

Appearances

 * Metal Gear Solid V: The Phantom Pain