Yes, these are Bat Nuts, but they are also called Water Caltrops, Buffalo Nuts, and Devil Pods. The starchy inner nut is eaten raw, boiled, or powdered and added to other foods. It's just one of a list of The World’s 10 Most Unusual Nuts. Would you rather try some candle nuts or tiger nuts? Read about these and more at WebEcoist. Link

(Image credit: Flickr user FotoosVanRobin)