Wikipedia
Elf-arrow
Elf-Arrows were arrowheads of flint used in hunting and war by the aborigines of the British Isles and of Europe generally, as they still are among native people elsewhere. Elf-Arrows derived their name from the folklore belief that the arrows fell from the sky, and were used by the Elves to kill cattle and inflict Elfshot on human beings. Also called 'pixie arrows', according to English folklore.
Elf-Arrows were sometimes worn as amulets, occasionally set in silver, as a charm against witchcraft.