Reefback Leviathan

The Reefback is currently the largest passive life form in Subnautica, belonging to the fauna category.

Appearance
The Reefback is massive in size, with most of the creature's body being comprised of a thick, purple carapace having a triangular front, and a relatively small body concentrated in the posterior. Attached to its main body are three long whip-like tentacles.

The carapace is patterned with slightly bright blue dotted pattern across towards the back. It also has many patches of teal coloured coral dotted across it, as well as some less prevalent, brown flora. Beneath its carapace, it is dark green with light blue bioluminescent stripes on the sides and in the middle. On either side of its body are eight yellow bioluminescent bulbs. The purpose of these is unknown, though the data bank entry notes a visual similarity to the Gasopod algae gland. Two siphon-esque structures are located next to these bulbs.

Behavior
The Reefback drifts slowly and gently around the open waters of many biomes, mostly seen swimming in pods of more than two. It almost never adjusts its current altitude, unless bumped against obstacles.

Juvenile Reefbacks that are a quarter the size of an adult, and have no coral or flora on their backs can be found with adults in certain locations.

The Reefback's unique trait comes from its ability to emit a wide range of echoing, low-frequency calls. Reefbacks will only emit these calls if there are other Reefbacks nearby, if not they will be silent.

Mini-ecosystem
Reefbacks can support mini-ecosystems on their back. These ecosystems include many types of flora and coral, along with other small fauna swimming in the vicinity of the gentle giants.

Fauna

 * Biter
 * Bladderfish
 * Boomerang
 * Eyeye
 * Holefish
 * Hoopfish
 * Hoverfish
 * Peeper
 * Shoal of Fish
 * Spadefish

Flora

 * Acid Mushroom
 * Furled Papyrus
 * Green Reeds
 * Red Branches
 * Regress Shell
 * Rouge Cradle
 * Tiger Plant
 * Veined Nettle
 * Violet Beau
 * Writhing Weed

Coral

 * Coral Shell Plate
 * Purple Brain Coral
 * Slanted Shell Plate
 * Table Coral

Barnacles are also found on their backs.

Gallery
In Game Screenshots=

Trivia

 * Reefbacks were initially intended to submerge themselves in sandy areas. Increased activity about them would've made them rise in search for a peaceful place to rest. It is unknown if this will ever be implemented.
 * Another intended interaction would've been that the player could grab a hold of the Reefback's tentacles to hitch a ride or hide on their plant-covered backs to hide from predators. It is unknown if this will ever be implemented.
 * Schools of Bladderfish can only be found near Reefbacks.
 * The Reefback has a top speed of 15 knots.
 * Reefbacks used to be smaller than they currently are, and had the same texture that is now given to juvenile Reefbacks. They were most likely increased in size due to them becoming dwarfed by other leviathans introduced around the time.
 * Reefbacks are most likely inspired by the Groveback from the novel 'Expedition'