"Sea snail" is the everyday name for any of the many edible marine gastropods — spiral-shelled molluscs such as the common whelk, periwinkle, conch, top shell and abalone's smaller cousins — harvested from rock, sand and seabed worldwide. The prize is the muscular foot: a dense, off-white coil of meat that is sweet, intensely briny and rich in oceanic umami, but naturally firm and chewy unless cooked with care.