Summary
There are thousands of survival games on the market, but one aquatic addition stands above the rest.Subnauticais a water-based survival game that pits players against the dangers of planet 4546B. The game’s unique elements and story have granted it worldwide fame and admiration. Every aspect ofSubnauticais amazing, but by far the most impressiveare its creatures.
From the big-eyed peeper to the peculiar Crabsquid, there is no creature lacking in creativity. While each creature is astounding, the most awe-inspiring is the Leviathan Class Organisms. Every one of these creatures is massive with some the size of buses and others the size of skyscrapers. While every Leviathan is huge fans would undoubtedly be surprised at how they compare.
Updated Jul 28, 2025, by Chris Harkin:The subject of leviathans is a popular one among theSubnauticafandom. There are many different species of creatures that count within these realms, from the moderately scary to the downright terror-inducing. WhileSubnautica 2is gearing up and looks set to bring even more monstrous creatures to the seas, fans of the franchise can have a look at the full list of creatures counted in the leviathan-class to date in the first two games of the series and debate which is the most terrifying and dangerous. TheSubnauticafranchise shows no signs of slowing down, and the leviathan creatures inhabiting these beautiful worlds are likely to keep growing in size and number.
15Squidshark
11 Meters
The Squidshark is the smallest creature in theSubnauticaseries (currently) that is considered a leviathan-class creature. It isn’t listed among them, but the data bank entry for this creature states “A leviathan-class predator at the smaller end of the scale,” which means that despite it appearing fairly rarely, the Squidshark is part of this group.
Appearing in the firstSubnauticagame and troubling players when they come anywhere near, the Squidshark is a unique amalgamation of two different creatures, bringing the terrifying parts of both its namesakes together. Though this creature isn’t that large, it is still much bigger than the player, and can easily kill them in just a few bites.
14Sea Treader
20 Meters
The Sea Treader Leviathan is notably unique compared to other creatures of its classification. While other members of its category swim or burrow, the Sea Treader walks. Using its two legs and elongated mouth — commonly mistaken for a third leg — it marches across the barren ocean floor. With each powerful step, the Sea Treader uproots ore from the ground for players to collect.
The Sea Treader is the smallest Leviathan known so far, but still measures 20 meters in size, which is considerably large. This bottom-dwelling Leviathan is nearly double the size of a bus. Even juvenile Sea Treaders are towering compared to humans. However, when in line with other Leviathans, the Sea Treader becomes far less imposing.
How To Deal With Sea Treaders
Sea Treaders are not aggressive; however, they will attack anything that approaches their herd. Using their powerful legs, they can easily bludgeon a careless diver to death. Thus, it is best to stay away from a Sea Treader’s path. If players are looking to collect uprooted ore, they should wait for these beasts to cross first.
13Glow Whale
30 Meters
The Glow Whale Leviathan exemplifies planet 4546B’swondrous icy ecosystem. Every aspect, from its bioluminescent properties to its harmonious sounds, inspires amazement. Witnessing Glow Whales breach the surface or consume schools of fish is astonishing, but players can take it one step further. These majestic creatures will allow players to pet or even ride them for a period.
The Glow Whale is the smallest Leviathan inSubnautica: Below Zeroand the thirteenth biggest overall. It is 30 meters in length and considerably broad in size. This fantastical Leviathan is slightly bigger than a basketball court. The Glow Whales massive body even supports barnacles and vegetation. Despite this compared to other Leviathans the Glow Whale is lackluster in size.
How To Deal With Glow Whales
Glow Whales are passive creatures that lack any defensive capabilities. Thus, there is no real need to fear or avoid these magnificent leviathans. One should take any opportunity to embrace these great beasts and even hitch a ride on their backs.
12Chelicerate
40 Meters
The Chelicerate Leviathan is only a sample of what4546B’s icy watershave to offer, and it is horrifying. At first, it is deceptively unimpressive, but upon getting closer, players will be met with true terror. When attacking, the Chelicerate’s jaw will split into four mandibles able to grip and swallow prey.
The Chelicerate is the smallest aggressive Leviathan of the series, and the twelfth largest of its kind. It is a size of 40 meters with its head making up a third of its length. This petrifying Leviathan is around the size of a smaller commercial airplane. Even with its void counterpart, the Chelicerate remains among the less impressive sized Leviathans.
How To Deal With Chelicerates
Chelicerates are aggressive creatures that are highly territorial, relentlessly pursuing anything that encroaches on their turf. So, it is understandably difficult to avoid or even escape these unyielding leviathans. The best way to deal with Chelicerates is to travel through crevices or maximize one’s speed. Otherwise, all players can do is hope that a Chelicerate does not notice them.
11Reaper Leviathan
55 Meters
The Reaper Leviathan remains one of the most notorious Leviathans in the franchise.This harrowing creatureacts as a reminder for players to always be cautious when exploring 4546B’s sea. Those unfortunate or careless enough to encounter the Reaper Leviathan will face the might of 4546B’s infamous killer.
The Reaper Leviathan is the second-smallest aggressive Leviathan inSubnauticaand the eleventh largest of its class, at 55 meters of pure muscle and murderous intent. This malicious creature is the size of the famous Leaning Tower of Pisa, large enough to crush vehicles with relative ease. It is one of the deadliest Leviathans, but far from being one of the largest.
How To Deal With Reaper Leviathans
Reaper Leviathans are aggressive creatures that attack with overwhelming ferocity. Thus, avoiding them is a priority, lest players are crushed by their powerful mandibles. A surefire way to avoid Reaper Leviathans is to stick close to the ocean’s surface, away from the deeper waters in which they lurk. Should players encounter this leviathan, it is best to move in a winding pattern.
10Shadow Leviathan
60 Meters
The Shadow Leviathanis among the series' most harrowing creatures. Every feature is meant to induce terror in players. The Shadow Leviathan’s slender black body and sharp protrusions are frightening enough, but its mouth is nightmarish. Located on the underside of its body is a glowing ribcage-like mouth.
The Shadow Leviathan is the second-largest aggressive Leviathan ofSubnautica: Below Zeroand the tenth-largest overall, at 60 meters in length. This horrific Leviathan is the size of a lower-end soccer field, big enough to grab the Seatruck and even swallow it whole. It is one of the most terrifying Leviathans, but also on the smaller end.
How To Deal With Shadow Leviathans
Shadow Leviathans are vicious creatures that prey on other leviathans and players unfortunate enough to be caught in their grasp. Their spectral mouth is capable of crushing and swallowing nearly anything, making them a significant threat. The preferred strategy for avoiding Shadow Leviathans is to stick to the ocean’s recesses, where it cannot reach.
9Reefback Leviathan
70 Meters
The Reefback Leviathans are among the most beloved creatures in the series. Their peaceful demeanor and great size make them one ofSubnautica’sgreatest wonders.Even seasoned playerscannot pass pods of Reefback Leviathans without admiring their majesty. In addition to their astounding presence, the Reefback Leviathans hold a mini-ecosystem on their shell.
The Reefback Leviathan is the largest passive Leviathan inSubnauticaand the ninth-largest of its class. It is a stocky creature that is 70 meters in length, the size of the world’s largest cargo plane. Adult Reefback Leviathans have no predators due to their massive size. Despite its amazing size, it is among the smaller Leviathans.
How To Deal With Reefback Leviathans
Reefback Leviathans are not only gentle giants, but an excellent source of material as well. Although they lack any offensive capabilities, Tiger Plants often seek refuge on their backs. This hostile flora can easily kill an unsuspecting player. Thus, it is best to observe from afar, and dispatch any Tiger Plants quickly with a Survival Knife or Thermoblade.
8Ice Worm
95 Meters
The Ice Worm Leviathan is the only member of its class to beentirely land-based. This massive creature burrows through the freezing ice shelves of 4546B. The Ice Worm uses its super-heated horn to drill through the planet’s ice near effortlessly. Using this ability, it can ambush prey above the ice within seconds. The only way to evade the Ice Worm is by using a Thumper, which will temporarily distract it.
The Ice Worm is the largest aggressive Leviathan inSubnautica: Below Zeroand the eighth largest of its kind. At 95 meters in length, this subterranean Leviathan is about the size of the famous Big Ben Clocktower. Its burrows are large enough to allow the Prawn Suit through with ease. The Ice Worm is among the bigger Leviathans, but it is still dwarfed by some.
How To Deal With Ice Worms
Ice Worms are very aggressive, with incomparable ferocity and impenetrable defenses, making it a difficult beast to counter. However, that is not to say that it is impossible. The best way to deal with Ice Worms is to rely on a device colloquially known as a Thumper. This tool will draw the leviathan’s attention, providing players ample time to escape or at least get a running start.
7Ghost Leviathan
107 Meters
The Ghost Leviathan is often regarded as one of the most terrifying Leviathans. Its translucent and luminous appearance makes it a supernatural-like creature of 4546B’s seas. Its skin alone is scary, but what lies beneath is much worse. Upon close observation, players will note that the Ghost Leviathan has a formidable musculature underneath.
The Ghost Leviathan is the third-largest aggressive Leviathan and the seventh-biggest overall. Its clear and slender body is 107 meters in length, nearly the size of a football field. It can easily destroy the submarine, making it a considerable threat. The Ghost Leviathan is one of the larger members of its class, but it is far from the biggest.
How To Deal With Ghost Leviathans
Ghost Leviathans are just as petrifying and dangerous as their name suggests. They are aggressive and can easily damage, overturn, and destroy the most formidable vehicles. Fortunately, Ghost Leviathans take time to charge an attack and often swim away afterwards. The best method is to move out of their attack path within moments of contact, evading their assault and granting time to flee.
6Ventgarden
110 Meters
The Ventgarden Leviathan is a remarkable example of symbiosis on planet 4546B. It cooperates with 4546B’s plant life to survive off a thermal vent alone. The Ventgarden’s transparent bell functions as a shelter for flora from herbivores. In turn, the plants help the Leviathan absorb various metals and gases released from the thermal vent.
The Ventgarden is the largest passive Leviathan of the franchise and the sixth biggest of its class, towering at a height of 110 meters. This plant nursery-like Leviathan is only slightly bigger than the Ghost Leviathan, and is large enough for players to enter it and explore.
