Selkies are waterfolk that are said to have the ability to shift between human and seal form. According to legend, in order to shift to seal form, they must have their seal-skin in their posession. Also according to legends, they are said to be at least partially responsible for storms, especially ones that sink ships. They are said to be the waterfolk cousins of the sidhe, and stories refer to them as being part of the Seelie and Unseelie Courts.