Moloch
From Official Barotrauma Wiki
Template:Stub The moloch are enormous crustacean creatures somewhat resembling horseshoe crabs. They have three long, armoured limbs with a large claw at the end.

They are slow and easy to spot in the radar due to their immense size, which makes them fairly easy to avoid. If they reach the submarine however, they can easily cause catastrophic leaks just by bumping their head against the hull.