Gumboot chiton

The gumboot chiton (Cryptochiton stelleri), also known as the giant western fiery chiton or giant Pacific chiton, is the largest of the chitons, growing to 36 cm (14 in) and capable of reaching a weight of more than 2 kg (4.4 lb). It is found along the shores of the northern Pacific Ocean from Central California to Alaska, across the Aleutian Islands to the Kamchatka Peninsula and south to Japan. It inhabits the lower intertidal and subtidal zones of rocky coastlines. The gumboot chiton's appearance has led some tidepoolers to refer to it, fondly, as the "wandering meatloaf". The name "gumboot chiton" seems to derive from a resemblance to part of a rubber Wellington boot or "gum rubber" boot.

Chitons are molluscs that have eight armored plates (called valves) running in a flexible line down their back. Unlike most chitons, the gumboot's valves are completely hidden by its leathery upper skin or girdle that usually is reddish-brown or brown, but occasionally is orange in color.

Chitons have long arrays of fine teeth that are partially made of magnetite, making its teeth hard enough to scrape algae off rocks. The styli enclosing their teeth contain the mineral santabarbaraite, making the gumboot the first organism known to use this material.