Triangular pieces of flint which appear all over the word. The name comes from their description in Scotland. Some claim they could be used as weapons by being hurled with great force. They were supposed to provide protection from fairies and could cure illness--at least illness caused by fairies. In fact, there were "fairy doctors," people who specialized in treating diseases caused by fairies. One cure of such a disease was to drink water into which an elf arrow had been dipped.