In Celtic folklore, kelpies lured people into the water with evil intent. For example, this shape-shifting creature could turn into a beautiful woman, coercing men into the water. Or the kelpie could remain as a horse and offer children rides on its back. Once its victims mounted, the kelpie’s smooth, seal-like coat would turn adhesive, and it would jump into the water, promptly drowning and eating its passengers.
Kelpies could be captured by anyone willing and able to get their bridles, the source of their shape-shifting abilities. This was considered any incredibly difficult task, though, since kelpies were associated with the “spirits of the dead.” Nonetheless, they were highly prized because of their strength and durability.