Iron-plated snail

A snail that lives near the hydrothermal vents in the Indian Ocean has developed an unusual defense mechanism: it uses the iron sulfide in the surrounding water to make an iron-plated shell with some interesting properties.

Part of its ability to resist damage seems to be the way the shell deforms when it’s struck: It produces cracks that dissipate the force of the blow, and nanoparticles that injure whatever is attacking it