Update: On June 2, 2018 I visited San Miguel Mercado in Madrid where I encountered the Spanish goosenecks I learned about in the Human Planet episode I referenced in the original version of this article.
According to a recent documentary I watched, Human Planet episode one, the Gooseneck barnacle is a delicacy men risk their lives to collect in Spain. Unlike Spain, these barnacles are plentiful and can easily be gathered around Jeju island. Today while on a mini vacation I spent some time near the sea wth Yunhee collecting them. Yunhee was more successful at dislodging them from their tight bind to the rocks. The barnacles can fetch as much as 800 euros in Spain, per kilo.