Every Subnautica monster explained: the biggest creatures, leviathan sizes, the Crabsquid EMP, and how to survive each predator.
Subnautica Monsters — Every Creature and Leviathan Explained
Subnautica's "monsters" are its fauna: three dozen species, from harmless peepers to the 112-meter Sea Dragon Leviathan that breathes fire at your Cyclops. If you're asking about the real monsters, you mean the leviathans — and the hierarchy is specific: Reaper Leviathan (55 m), Ghost Leviathan (107 m), Sea Dragon Leviathan (112 m), and the Sea Emperor (160–200 m), the largest living creature in the game. This guide is the full bestiary of the things that can kill you — sizes, HP, damage, spawn zones, and how to survive each one.
Here's what you'll learn:
- Every leviathan class monster with exact size, HP and damage numbers
- The biggest creature question, answered definitively
- The Crabsquid and its EMP mechanic, in detail
- All the mid-tier predators and where they live
- Whether leviathans can be killed (and the consequences)
Official resources: Steam store page · Official Subnautica Wiki — Leviathans · Official Subnautica Wiki — Crabsquid · Wikipedia — Subnautica
What Is the Biggest Monster in Subnautica?
The answer, verified against the official wiki and cross-checked with the creature pages: the Sea Emperor Leviathan is the largest living creature, at 160–200 meters — bigger than the Sea Dragon (112 m), the Ghost (107 m) and the Reaper (55 m). The catch: the Sea Emperor is passive, caged, and only met at the end of the story (full guide here).
The largest aggressive monster is the Sea Dragon Leviathan (112 m). And the largest thing ever recorded on 4546B is neither: it's the Gargantuan Leviathan, known only from its fossil — a 402-meter skeleton in the Lost River's Bone Fields that is only about a third of the whole creature, with a skull so large a Cyclops fits inside its jaws (official wiki). The living species was cut from the game; the fossil is its monument.
| Creature | Length | HP | Attitude | Where |
|---|---|---|---|---|
| Sea Emperor Leviathan | 160–200 m | n/a (uncapturable) | Passive | Primary Containment Facility |
| Sea Dragon Leviathan | 112 m | 5,000 | Aggressive | Inactive Lava Zone, Lava Lakes |
| Ghost Leviathan | 107 m | 8,000 | Aggressive | Grand Reef (2), Northern Blood Kelp (1), Crater Edge (endless) |
| Reaper Leviathan | 55 m | 5,000 | Aggressive | Crash Zone, Dunes, Mountains, Bulb Zone |
The Leviathans in Detail
Reaper Leviathan (55 m, 5,000 HP)
The game's poster monster and its most dangerous early encounter. Spawn zones: the Crash Zone around the Aurora, the Dunes, the Mountains, and the Bulb Zone. Damage per the official wiki: 80 to the player, 220 to the Cyclops, 40–60 to the Seamoth, 20–30 to the Prawn Suit. Its grab attack is a kill move — if the next attack would kill you, it grabs instead. It's also the source of the game's most famous meme (memes guide): the PDA's "Detecting multiple leviathan class lifeforms" warning.
Reapers are faster than you on a straight line but can't turn well. Serpentine with the Seaglide, or better: don't be in their zones without a Seamoth. In the Cyclops, kill the engine when it grabs — creatures lose interest in a silent sub (full noise math in the Cyclops guide).
Ghost Leviathan (107 m, 8,000 HP)
Three adults spawn on the map — two in the Grand Reef and one in the Northern Blood Kelp Zone — plus endless Ghosts in the Crater Edge, the map's border guards. Three juveniles (67 m) live in the Lost River before migrating out as they mature. Damage: 84 to the player, 250 to the Cyclops. They're faster than Reapers and their habitat overlaps the mid-game exploration routes — the Grand Reef, for example, is a major resource biome (Grand Reef guide).
Sea Dragon Leviathan (112 m, 5,000 HP)
The endgame fire-breather, found in the Inactive Lava Zone and Lava Lakes. Per the official wiki: its bite is an instant kill on a player, its fire breath deals 500 damage to the Cyclops and starts onboard fires, and it's immune to the Thermoblade. It's the reason the last stretch of the game is played in a shielded, fire-suppressed Cyclops.
Sea Emperor Leviathan (160–200 m, passive)
The largest, oldest (2,600 years), and the only friendly leviathan — the Sea Emperor guide covers the full story, but the short version: it's the source of the Enzyme 42 cure, and it never attacks you.
The Crabsquid and Its EMP
The Crabsquid isn't a leviathan, but it's the monster players ask about most, so it gets its own section. Stats from the official wiki:
| Stat | Value |
|---|---|
| HP | 500 |
| Slash damage | 40 |
| Special | EMP blast — disables electronics temporarily |
| Size | 3×3 (9 inventory slots) |
| Biomes | Deep Grand Reef, Grand Reef, Northern Blood Kelp, Lost River (Corridor, Ghost Canyon) |
| Attracted to | Light sources — it EMPs when close to one |
How it works in practice: the Crabsquid clicks loudly (that's your warning), then, if it gets near a light source — your Seamoth's lamps, your base lights, your Cyclops — it releases an EMP that knocks out electronics for a few seconds: your Seamoth stalls, your Cyclops loses power briefly, your base lights flicker out. Counters: turn your vehicle lights off in Crabsquid territory, keep distance, use a Creature Decoy, or just kill it — it flees after two knife hits or one Thermoblade hit.
Per the official Crabsquid wiki entry: "The Crabsquid is attracted to any light source. Upon getting close to a light source, they will release an EMP Blast. This blast will temporarily disable certain tools, vehicles and seabases."
The Mid-Tier Predators
| Monster | HP | Attack | Where | Threat |
|---|---|---|---|---|
| Stalker | 300 | 30 per bite | Kelp Forest | Low — the classic "first predator"; loves metal salvage |
| Sand Shark | 250 | 30 | Grassy Plateaus | Low — buries in sand, ambushes |
| Boneshark | 200 | 29 vs player, 15 vs Seamoth | Grassy Plateaus, Crash Zone, Mushroom Forest | Medium — swarms, gnaws vehicles (won't damage the Cyclops hull) |
| Warper | 100 | Claw 23–69; warp projectile 10 | Grand Reef, Lost River, Lava zones | High — can warp you into a leviathan |
| Mesmer | 100 | 35 bite | Sparse Reef, Crag Field edges | Medium — it makes you swim into its mouth; the fish's glow is the lure |
| Crabsnake | 300 | 35 vs player, 17 vs Seamoth | Jellyshroom Caves | Medium — hides in the pink mushrooms |
| Ampeel | 3,000 | 45 bite + 15 shock | Blood Kelp, Bulb Zone | Medium — shocks the Seamoth |
| River Prowler | 150 | ~20 (unverified) | Lost River | Low-Medium — Lost River's local teeth |
| Lava Larva | 100 | None (leech) | Lava zones | Annoying — attaches to the Cyclops and drains it; remove with knife or Propulsion Cannon |
| Reefback Leviathan | 10,000 | None (passive) | Across the map | None — the friendly giant; its barnacles hold resources |
Warpers don't deal huge damage — they teleport you out of your vehicle and into open water, often into a leviathan's patrol line. The famous "warped straight into a Reaper" clips are a Subnautica rite of passage. If you see the purple warp shimmer, swim away from it, not toward it.
Can You Kill a Leviathan?
Yes, and it's worth knowing the consequences. With the Stasis Rifle + Thermoblade (slow), or the Prawn Suit's Drill Arm (faster), you can kill anything with HP — the 5,000–8,000 HP leviathans take a while but it works. What the game does NOT do:
- Leviathans do not respawn after death (except the Crater Edge Ghosts), so killing one permanently clears its territory — the community's "Reaper genocide" runs are a real thing.
- There's no reward beyond the territory — killing a Reaper with the Prawn drill doesn't drop loot. The community's "Reaper genocide" runs, where players hunt every Reaper across the map, are purely a hobby.
The Sea Dragon is immune to the Thermoblade, its fire breath starts fires inside your Cyclops, and its bite is an instant kill. The only sensible play is avoidance: Silent Running past the Lava Lakes entrance, decoys on cooldown. This is the one monster you cannot out-brawl.
The Bigger Picture: Fauna Families
If you're here for "how many monsters are there": Subnautica's fauna breaks into herbivores (peepers, boomerangs, garryfish, hoverfish, reginalds, spadefish, the Cuddlefish, etc.), carnivores (everything in the tables above), and leviathan class (the top four). The full species list with stats lives on the official wiki's Fauna page. The Peeper guide covers the harmless half of the ecosystem in detail.
FAQ
What is the biggest monster in Subnautica?
The Sea Emperor Leviathan at 160–200 meters — but it's passive. The biggest aggressive monster is the Sea Dragon (112 m), and the largest ever was the cut Gargantuan Leviathan, known from a 402-meter fossil that's only a third of the skeleton.
How many leviathans are in Subnautica?
Four species: Reaper (55 m), Ghost (107 m), Sea Dragon (112 m), Sea Emperor (160–200 m) — plus the Reefback, which is leviathan-class but harmless, and the fossil-only Gargantuan. Multiple individuals spawn per species.
What does a Crabsquid do?
It's an aggressive 500-HP predator that's attracted to light and fires an EMP blast when close, temporarily disabling your tools, vehicles and base electronics. It slashes for 40 damage and lives in the Deep Grand Reef, Northern Blood Kelp and Lost River.
Where do Reaper Leviathans spawn?
The Crash Zone (around the Aurora), the Dunes, the Mountains, and the Bulb Zone. The Aurora's bow and the Dunes are the classic spots where new players meet their first one.
Can you kill a leviathan in Subnautica?
Yes — Stasis Rifle + Thermoblade or a Prawn Suit Drill Arm can kill any leviathan, and they don't respawn. There's no loot reward, but clearing Reaper territory is a popular endgame project. Don't try this on the Sea Dragon (Thermoblade-immune, instant-kill bite).
Related Guides
- Subnautica Sea Emperor — Story, Location & Blue Tablet
- Subnautica Grand Reef — Biomes, Resources & Map Spots
- Subnautica Peeper — Locations, Food & Eye Facts
- Subnautica Cyclops Guide — Fragments, Upgrades and Pilot Tips
Last updated: August 13, 2026.
More Subnautica Guides
Every leviathan in Subnautica and Below Zero: sizes, aggression, spawn biomes, health and how to deal with each — plus the extinct giants.
How to enter the Aurora in Subnautica: every door code (1454, 1869, 6483, 2679), the radiation suit requirement, what tools you need and all the loot inside.
All Subnautica Aurora door codes: 1454, 1869, 2679 and 6483, where each code is found, and exactly what's worth looting behind every door.
Subnautica Below Zero map explained: how big Sector Zero is, every biome with depth ranges, key coordinates, navigation tips and the best map mods.
Is Subnautica Below Zero multiplayer? No official co-op — but a full story-synced mod exists for Windows. Plus Nitrox and Subnautica 2's official co-op.
Subnautica Below Zero Picture Frame guide: the 16:9 aspect ratio you need for photos, where to get the blueprint, and how to load custom images.
Official Subnautica Below Zero pictures and 16:9 wallpapers: where to download store screenshots, wiki art and community shots in full HD.
The Subnautica map explained: all 18 aquatic biomes with depth ranges, resources and dangers, plus how to navigate without an in-game map.