pouce-pied

Pouce-pied or goose barnacles are also known as operne, pied de biche, pas-e-bez (in Brittany) or lanterna in the Basque country or percebes in Spain, where these stalk-barnacles are a sought-after and extremely expensive delicacy. They live on rocky shores of exposed coasts, in the intertidal zone, often in dangerous spots that make harvesting them difficult...hence the high price.

The English name comes from a supposed sighting of a goose hanging upside down from the barnacles in the Middle Ages, and another writer claiming he spotted the birds hatching out of the barnacles. Until the 18th century no one knew the geese actually migrated north to the Arctic and and did their breeding there.