Opihi is a Hawaiian delicacy. It's a limpet that lives on seaside rocks (they are notoriously hard to pry off). Opihi cling to rocks. Not just any ordinary rock, but seaside rocks along Hawaii's ocean coastline. To get opihi, you have to maneuver yourself along these giant rocks and use your hands to pry the opihi off the rocks (some people use butter knives, others use paint scrapers) one by one. It is not easy! If you miss pulling the opihi off the rocks on your first try, odds are that you'll never get that one. The opihi panic and the "foot" of the opihi clamps itself down on the rock so tight that it is impossible to get off. Time to move on to the next one.