Belon is a river in France famed for succulent oysters. Belon, you will point out with a pinch of Gallic disgust, is not in Maine. No, but the oyster that made Belon famous—The European Flat—is. Scientists brought European Flats to Boothbay Harbor, Maine, in the 1950s, and they went feral (the oysters, not the scientists). These wild oysters are as powerful as any on the planet, redolent of fish and zinc and umami—not for the faint of heart. A minuscule 5,000 Belon a year are pulled in Maine and sold, making them one of the rarest oysters in the world. If you are lucky enough to get your hands on a few, savor them. You may hate them, you may love them, but they will make an impression.