In the past, Scottish peasantry believed that elf arrows or elf shots (arrowheads of flint) also known as Belemnites fell from clouds and were used as weapons by fairies, elves, and witches to destroy cattle and humans. However, once these arrows were in the possession of humans, they could be used as talismans against witchcraft and evil eyes, as well as a cure for cattle that have been afflicted.
Sources and further reading
Spence, Lewis. An Encyclopaedia of Occultism. New York. University Books. 1968. p. 139