The "giant clam" players keep spotting in Subnautica 2 is the Great Jaw, a stationary Leviathan-class creature nicknamed Clamthulu during development. It sits in the open ocean with its shell parted, dangles tripwire tendons across the opening, and snaps shut on anything that disturbs them.
Where the Great Jaw spawns
The Great Jaw is not tied to a single biome. Several specimens are seeded across the open ocean, and at least one is placed along the early progression path while you are hunting Tadpole submarine fragments. Collector Leviathan lairs in the deep chasms also contain shells of smaller, gutted Great Jaws — the "mini-Clamthulus" — but those are corpses, not live encounters.
| Location | How to reach it | Notes |
|---|---|---|
| Third Tadpole fragment site | Follow the Tadpole submarine fragment quest line to the third fragment | Most reliable live spawn; loot inside includes a Portable Oxygen Generator blueprint |
| Open ocean, multiple sites | Search wide stretches of open water at mid depths | Specimens are scattered; sizes vary because adults grow over decades |
| Collector Leviathan chasms | Deep chasm areas where Collectors hunt | Only emptied shells from juvenile Great Jaws; no live trap mechanic here |
How to identify a Great Jaw on sight
Look for a massive bivalve resting on the seafloor with its two mineral shells held open. Inside, a fleshy mantle lines the interior, the eyes sit along the inner rim, and thin tendons stretch across the opening like tripwires. A glowing object or visible loot is often staged in the center — that bait is deliberate. The creature uses it to pull divers inside.
How the trap works
The tendons are attached to the adductor muscles. Brushing one wakes the eyes, and if the Great Jaw sees you while a second tendon is disturbed, the shells slam shut. Once closed, the interior fills with domoic acid neurotoxin and the creature begins to digest whatever is trapped inside. There is no fight phase. Escape comes from prevention, not combat.
Safely entering for loot
Step 1: Park your Tadpole outside the shell rim and approach on foot. Vehicles are too large to maneuver between the tendons without snagging them.
Step 2: Identify the tripwire tendons stretched across the opening. Cut or avoid them one at a time, and break the line of sight with the inner eyes between cuts so the closure reflex does not trigger.
Step 3: Grab the staged loot in the center — commonly a Portable Oxygen Generator unlock, plus lithium nodules embedded in the mantle. Then exit the same way you came, watching for any remaining tendons on the way out.
You will know you triggered the trap when the eyes track you and the shells begin to close. If both halves meet, you are dead. There is no in-fight counter.
What the Great Jaw drops
| Resource | Why it matters |
|---|---|
| Lithium pearls | The Great Jaw bioaccumulates lithium and expels nodules; a primary source for the material |
| Portable Oxygen Generator blueprint | Staged inside as bait at certain spawns; unlocks the deployable on pickup |
Not to be confused with the Collector
The Collector Leviathan, the giant squid-like predator seen in trailers, actively hunts juvenile Great Jaws and tears them open. If you find a Great Jaw shell that is already split, hollowed out, and clearly dead, you are inside a Collector's territory and should leave before it returns. Live Great Jaws are intact, open, and baited; gutted shells mean a much faster predator is nearby.
For the trap encounter itself, the safest approach is the third Tadpole fragment route — that placement is deliberate, the loot inside is worth the visit, and once you understand the tendon-and-eye mechanic, the Great Jaw becomes one of the few Leviathans you can actually walk away from.