Zellislava

A Zellislava is a ship which a group of Zells have entered into a dream with. The ship itself forms as the nexus of the dream, which is also a hivemind between the zells, and the ship therefore becomes altered, taking on a life of its own.
The specifics very much depends upon several factors. Which of the Seven is the ship aligned with? A Tesshechtite ship will tend to be blocky, angular, huge, powerful. A Dakonat ship will tend to be sleek, sinuous even, with textured cheeks like rippling thews, and rigging straining at the masts, creaking as though with anticipation.
But beyond just the deity, there is also the material, and the temperament of the crew. A Zellislava can only build itself out of what it can acquire, after all. Junk left laying around is usually absorbed, as are bones, driftwood, seaweed, even corpses if such things are available. The ship takes them when nobody is looking, and incorporates them into itself. The shape and size of the ship definitely change over time — though the exact mechanics of this are unclear, and the results rarely conform to any standard model of ship. The Zellislava is held together by the power of the Dream — only the oldest of them can endure past the deaths of their crews. A Zellislava whose Zells die usually collapses into flotsam on the spot. Those that survive wander the seas, lonely, heartbroken even, and eventually beach themselves somewhere to rot away.
There is a story, unverified but nonetheless popular among landbound zells, of a group of teens born to human mothers finding a great and ancient Zellislava in this state, convincing it to give them a chance, and instantly becoming wealthy and powerful.