Summary
Subnauticais anopen-world action-adventure gamewhere players have to survive the deep oceans on an alien planet. Everyone knows that our planet’s oceans are filled with uncovered secrets and mysteries. But for the creators ofSubnautica, that wasn’t enough, so they introduced the terrifying underwater ecosystem of planet 4546B.
Some creatures are mesmerizing, some arebreathtakingly beautiful, and some are even adorable, but most are either scary or just unsettling. A lot of these alien lifeforms might look disturbing for players, leaving them uncomfortable just looking at them. For this list, we’ve gathered all thescariestSubnauticacreaturesthat make the hair stand up on every player’s back and ranked them according to their actual strength.
Updated on June 11, 2025, by Mati Kent-Nye:With the highly anticipated release of Subnautica 2 into early access right around the corner, there’s no better time for players to reacquaint themselves with the terrifying creatures that lurk in the depths of planet 4546B. Subnautica 2 may take place on a new planet, but there will likely be some similarity in the types of life it harbors. They’re both oceanic planets, after all! Now is the time to refresh that knowledge and prepare for a new underwater adventure.
Subnautica’s oceans still amaze players, who continue to find wondrous and shocking things lurking in its depths. This list has been updated to include even more terrifying aquatic monsters.
25Research Specimen Theta
Intimidating Predator With a Tragic Story
This mysterious skeleton only appears in the Architects' research facility in the Lost River labeled as “research specimen theta.” From what can be discerned, it would have been an imposing predator. The heavy-plated bones and blunt jaws appear similar to Dunkleosteus, a real prehistoric apex predator, characterized by a jaw that could bite harder than any living shark today. Imagine something like that, but over twice as big, with more armor and four eyes. This could easily have split Riley in half with one hit.
Piecing together the clues left in the facility paints a bleak picture of its life. Theta appears to have been captured and put into an aquarium for study, where it might have been deliberately infected with the Kharaa virus. Its remains are still there when Riley arrives, suggesting one of two outcomes: either it was terminated when the Architects evacuated the lab, or it was simply abandoned and left to die of starvation.
24Blood Crawler
Swift, Unpredictable Movements & Spider-Like Appearance
Gamers who lovescary video gameswill enjoy getting to knowSubnautica’s creepy Blood Crawler. This nightmarish being has spindly legs and sharp, elongated appendages, resembling a cross between a crab and a spider. Thanks to its swift movements and aggressive nature, it is a formidable challenge, especially for new players who are just learning how to navigate the game’s complex ecosystem. While it might not be a gigantic beast, it is a dangerous creature that has startling speed and can appear suddenly seemingly out of nowhere.
Dealing with a Blood Crawler requires a blend of caution and quick reflexes. Players are advised to maintain a safe distance and use ranged tools or weapons for defense. In situations where escape is the only option, swift swimming or the use of vehicles like the Seamoth can provide a crucial advantage in evading these menacing creatures.
23Shuttlebug
Eerie, Unsettling, Spider-Like Creature
The Shuttlebug inSubnauticaearns its reputation as one of the game’s scariest creatures not through direct threat or aggression, but through its ability to create an eerie and unsettling atmosphere. This visual eeriness, combined with its behavior of suddenly appearing and disappearing in the murky waters, can startle players, especially in the game’s immersive, deep-sea environment.
Although the Shuttlebug isn’t as aggressive as some ofSubnautica’sother inhabitants, it still can be quite startling, particularly for new players. Gamers can find Shuttlebug mostly in the shallower areas, and it’s often one of the first mysterious creatures they’ll encounter, which adds an element of surprise to the game. Observing from a distance or gently steering clear is usually the best course of action.
22Stalker
Fearsome Predator With Sharp Teeth & Aggressive Behavior
Subnauticaplayers know that Stalker is a true terror of the deep. This creepy creature is one of the mostterrifying monsters in gamesand has a predatory fish vibe that’s complete with razor-sharp teeth and a body built for speed. Its piercing blue eyes and metallic gleam make it look like the ocean’s own terminator. They’re also pretty fast, unpredictable, and love to charge at players when they least expect it.
Players will have to use their strategic thinking if they want to deal with the Stalker successfully. Avoiding carrying metallic items will reduce the likelihood of attracting their attention as Stalkers love metal. If confrontation is inevitable, it is best if players try to distract the Stalkers by deploying metal salvage until they can escape.
21Ancient Skeleton
The Remains Of A Terrifying Predator
This skeleton is so old it doesn’t even have a name, though the popular fan nickname is “Titan Leviathan.” There isn’t a lot known about it, especially since only one skeleton has been found, but it seems to be a large predatory creature from a time when Leviathan-class creatures were even more common than they are now. The part that is visible has teeth of similar size to Riley’s body, and he can literally swim through a gap in the creature’s jawline.
It is theorized that this creature would have been able to easily take on reaper leviathans or sea dragons, while its armored plating would have protected it from most injuries. The question of the mysterious large holes in its rib cage, of which there are at least five on each side (assuming more aren’t hidden in the buried portion of the skeleton), doesn’t help. The player’s imagination is left to run wild about what these were for.
20Lava Lizard
Aggressive, Dangerous, Delivers Strong Attacks
Subnauticais an excellent game for those players who lovecreature collection gamesand Lava Lizard is one of its most aggressive creatures with a fairly strong attack that causes 30% damage to players. This creepy Subnautica creature can not only bite players but spit lava at them.
While Lava Lizards are only mid-sized they’re still feared thanks to their hostile and violent behavior and considerable high attack damage. Players can find these carnivorous monsters at the Lava Lakes, the Inactive Lava Zone, or while exploring the Lava Castle. Even though Lava Lizards are hostile, players can choose not to interact with them, or they can also use Lava Larvae as bait because the Lava Lizard will just eat the Lava Larvae and leave the player alone.
19Reefback Leviathan
Massive, Alien, Intimidating
Likely the first leviathan species new players will encounter, these massive beasts are sure to give them a fright. These alien, almost non-sentient-looking creatures roam the open waters of these worlds, striking fear into the hearts of players who do not know they’re peaceful giants. Only by overcoming this fear and approaching these leviathans will players realize that these creatures are in fact helpful, offering players an abundance of minerals and food to harvest.
Watching these monsters swim by is a stark reminder to players that this oceanic world is a far cry from Earth. They best be ready to expect the unexpected if they’re to stand any hope of survival.
18Boneshark
Large, Fast, Aggressive, Powerful Bite
Boneshark is one of the largest and most aggressive shark-likeSubnauticacreatures. These hostile monsters not only have a scary look, but they’re actually pretty fast and can easily catch up to players. Bonesharks also have a bite that causes 30% damage.
Players can encounter these carnivorous creatures at multiple locations including The Crash Zone, Underwater Islands, Bulb Zone Biomes, and Crag Field. These highly aggressive predators are infamous for fiercely defending their hunting ground and players' best option to deal with them is to use flares when they’re attacked by a Boneshark. Bonesharks are attracted to lights, so they will attack the light instead of the players.
17Crashfish
Explosive, Fast, Dangerous
Looks can be deceiving inSubnautica. These small fish may look cute, but they’re in fact early-game terrors, lurking in Safe Shallow Caves ready to rush towards and blow up in the face of any player foolish enough to enter their territory. Even a single Crashfish attack is devastating for new players, dealing a massive blow to their health bars. There’s nothing quite so scary as exploring dark and narrow caves only to see an explosive fish rapidly approaching.
Encountering an abundance of Crashfish is all but guaranteed in any playthrough. Not only are the caves in which they reside rich in Limestone and Sandstone Outcrops, but the Sulfur Plants in which these fish hide are also the only source of valuable Cave Sulfur.
16Crabsnake
Grotesque, Surprise Attacks, Immobilizes Its Prey
Players who lovemonster-tamer video gameswill love interacting with Crabsnakes because of their unique behavior. Crabsnakes are also some of the most nauseating-lookingSubnauticacreatures that can get easily agitated by players. When Crabsnakes attack they cause 35% damage while also making players immobile for a while. However, they often decide to just patrol the area or simply go back to their Jellymushroom.
Since Crabsnakes love to hide in their Jellymushrooms to surprise attack players it’s fairly difficult to avoid them. However, players' best option is to avoid Jellymushrooms and swim as far away from them as possible, or they can also use their vehicle.
