Nay-Churr

Nay-churr (singular and plural) are a rare, scattered species of unknown ancient origin. Mostly they cruise the currents of the flame-sea, though some wander inside a crystal shell, and they survive in any environment. Builds vary, but every one is chiefly a stomach: a stony yet flexible hide shaped like a tapering tube when empty. At one end sits the maw, a long, rectangular slit at rest that stretches many times wider when feeding; in the largest kinds it can gape 500 feet across. Size and Hit Dice vary by type.

A nay-churr has no idea how to fight; it is all but mindless (roll to hit normally for anything it bumps into). It simply drifts along gulping whatever fits in its maw. Swallowed things are not harmed: crews and whole ships can ride inside indefinitely and come out unhurt. Its treasure is whatever it holds right now, from rubble and wreckage to working gear and intact vessels.

The best tactic is avoidance, which is easy, since it is slow and turns badly. If you must fight, say to rescue a swallowed friend, aim at the tender flesh around the maw. Brought to 0 hit points through maw hits, it vomits out its contents and goes inert, neither moving nor eating, for up to several weeks, but it is still alive.

Only hits on the stomach alone can kill it. At 0 hit points the stomach bursts 1d6 rounds later, slaying the creature, dealing 10d10 to everything inside and 5d10 to everything within 200 feet. For those trapped within, the remedy may be worse than the problem.

Cutting your way out is a bad idea. Any damage to the inner wall throws it into panicked convulsions: it lunges ahead at movement 18, thrashing side to side, and everything inside is hurled about too hard to attack, taking 1d10 per round from collisions.

The flame-sea is its native home and favorite place, where it can swim forever through endless, never-filling ether. Some slip into the void between worlds through an opening in a crystal shell, since they cannot breach one on their own. It empties itself willingly only inside the air envelope of something too big to swallow, like a world or a vessel of 100 tons or more, producing a downpour of debris toward that body's gravity plane.

Beyond its blind urge to swallow, it plays no role in the multiverse. A large enough piece of outer stomach wall salvaged after an explosion can be shaped into a breastplate that keeps its AC of -2.