From "All the Light We Cannot See" by Anthony Doerr
The aging mollusk expert, Dr. Geggard said to her: "Now that shell belonged to a violet sea snail that lives its whole life on the surface of the sea. As soon as it is released into the ocean, it agitates bubbles, and binds those bubbles with mucus, and builds a raft. Then it blows around, feeding on whatever floating aquatic invertebrates it encounters. But if it ever loses its raft, it will sink and die."
The aging mollusk expert, Dr. Geggard said to her: "Now that shell belonged to a violet sea snail that lives its whole life on the surface of the sea. As soon as it is released into the ocean, it agitates bubbles, and binds those bubbles with mucus, and builds a raft. Then it blows around, feeding on whatever floating aquatic invertebrates it encounters. But if it ever loses its raft, it will sink and die."