Sea Emperor Leviathan

The Sea Emperor is a work in progress creature that is currently spawnable in Subnautica. It can move, but it has no animation yet. It can attack the player and it emits a noise resembling that of a Bone Shark.

The Sea Emperor is spawnable in experimental mode using the command SPAWN LEVIATHAN.

The Cyclops is currently about 2.75 times longer and about 2 times higher than the Sea Emperor. The Sea Emperor currently deals about 30 damage to the player on attack. However, the Sea Emperor will be upscaled in the future. Then, it will be bigger than the Reaper Leviathan which is currently the biggest animal in Subnautica.

Speculation
Due to its very similar looks, it might be related to the Warper.