Kharaa Bacterium

Carar is an alien bacterium created by the Precursor Race for unknown reasons. It seems to have completely taken over Planet 4546B. It is described in the Degasi PDAs as "part of the ecosystem", with further suggestions that the Degasi survivors were infected at some point - as stated by Bart Torgal while discussing the flu-like symptoms the crew was experiencing. Early on, the player's PDA and Lifepod will make note of the high levels of bacterial infection in the water.

It is stated in Precursor data that the Carar bacterium has killed over 143 billion creatures over the course of time since it's creation. After a Sea Dragon Leviathan damaged the Disease Research Facility in an attempt to retrieve its offspring, the previously contained Carar bacterium was released onto the planet. This decimated the planet's ecosystems, as much of the life on the planet died due to the bacterium's immuno-repressive behaviour and genetic corruption. This prompted the Precursors to initiate their emergency quarantine: activating the Quarantine Enforcement Platform. The Quarantine Enforcement Platform shoots down all approaching or departing spacecraft to prevent Carar being spread to other planets.

The PDA estimates that Carar incubates in two weeks and kills in five weeks - it accomplishes this by shutting down the immune system (already making the infected host susceptible to other diseases) and causing genetic damage to the host's DNA, eventually leading to a total shutdown of the organism due to its inability to keep functioning properly.

Warpers were created to keep the levels of Carar to a minimum, to do so they will attempt to kill infected fauna, in an effort to control the spread of the bacterium. Though this seems to have been ineffective as Carar is still ravaging the planet a little under one thousand years after it was initially released.

The player is infected with Carar, though they only become aware of it after attempting to disable the Quarantine Enforcement Platform, as the deactivation terminal will tell the player that they are infected and therefore cannot use it, thus forcing the player to follow the story and secure a cure in order to leave the planet. The infection only becomes noticeable when the player reaches the Disease Research Facility and is prompted by the PDA to perform a self-scan. At this point it will warn the player that the infection is reaching a critical stage and the player's skin breaks out into glowing green cysts.

If an infected creature is placed inside an Aquarium or Alien Containment, the creature will infect the rest of the creatures inside soon after. However, this is purely cosmetic and has no impact on gameplay.

The player can scan fauna that have been scanned previously to check if they are infected with Carar.

It seems that the only way to cure Carar is with enzymes produced by the Sea Emperor and its young, as shall be shown by creatures being cured by the enzymes in the Sea Emperor's aquarium.

The Sea Emperor and the Warper are immune to the Carar bacterium, as they both play a role in eliminating it - with the Sea Emperor producing Enzyme 42 as a countermeasure, and the Warper being the result of its bio-mechanical adaptations implemented by the Precursors.

Appearance
Carar manifests itself in bright green cysts, along with similar colored veins spread throughout its host. The cysts start out as small protrusions, however, as time goes on, the cysts will grow larger and glow more strongly, signifying the organism is close to death.

Data Bank Entries
Infection Results= Research Bacteria Profile=

Gallery
In Game View=

For a more complete gallery, visit Carar/Gallery.

Trivia

 * The way that Carar manifests itself is loosely based on the appearances of the Kharaa from Natural Selection 2, as the Kharaa have similar looking cysts on their body - a "secret" data-log further supports this by explicitly naming the Kharaa and the fight against them as happens in Natural Selection 2.
 * The texture of Carar cysts on the player will be limited only to the hands, since these are the place with visible skin on the player.
 * Carar making multiple species extinct might mean that concept art creatures are canon, but have gone extinct due to Carar.
 * The Player is infected straight from the start of the game, despite not going in the water. It is theorized this will be fixed in the future.
 * Cory Strader has said that Kharaa from Natural Selection 2 is a mutated form of Carar, Scott MacDonald (Obraxis) followed this up, saying that "evolution" is why the Kharaa have yellow cysts and the Carar in Subnautica has green cysts.
 * Later, however, Cory Strader said to not take everything as canon, as the story links between Natural Selection 2 and Subnautica have not been set in stone.