Devil's Pod (also known as "Bat Nut") is the seed of an aquatic plant the Caltrop, which is used in spells for protection against evil. The demonic appearance of the nut drives away anything negative (a classic example of an apotropaic charm.) You can dress Devil's Pods with Protection Oil and hang them with their "face" outward to deflect evil sent your way. Some practicioners carry the seed pod in a red bag, an all-purpose protective bag.
Devil's Pod can also be offered to dark forces to appease them or keep them on your good side.