In 2001, on an expedition to hydrothermal vent fields in the Indian Ocean, researchers made a bizarre discovery. Clustered in small aggregations around the base of a black smoker was an unusual snail, seemingly clad in a suit of armor. Rather than a single, hard, calcareous structure, the snail’s operculum was covered in a series of tough plates. On recovery to the surface, those plates, as well as the snail’s heavy shell, began to rust. This was an Iron Snail.