Bioluminescence

Bioluminescence is a type of illumination created by some life forms in Subnautica. Most bioluminescent life forms cannot generate light bright enough to actually help the player with night time navigation.

Trivia

 * The Stalker and Lava Lizard are the only two fauna having no true bioluminescent glands.
 * Bioluminescence is used by many real-life animals for counter-illumination, luring prey, attracting mates, confusing predators, mimicking other animals, communication, and as a warning to would-be predators.