Happy Halloween! The Water Caltrop, aka Bat Nut, Buffalo Nut, and Devil Pod, is a type of nut that is similar to a Water Chestnut. They have a mild-nutty flavor and fibrous-starchy texture and need to be cracked open to get to the flesh. Boil, simmer, or roast and use for a snack, in a stir-fry, or for a stuffing.