Lobster is the sweet, briny, faintly mineral flesh of a large clawed marine crustacean — the meat of a slow-growing, hard-shelled animal that turns from mottled blue-black to brilliant red the moment it meets boiling water. Prized in the muscular tail and the pair of heavy claws, it cooks to a firm, glistening, delicately sweet flesh that is among the most luxurious of all seafood.