The Kelpie is a carnivorous, shapeshifting water demon that dwells in the lochs and pools of the Scottish Highlands. They lie in wait by the shore, disguised as a wild pony, and entice children to ride on it’s back. Once the child is aboard, Kelpies will dive into the swirling waters and drown the child, devouring everything except the heart and liver which it then leaves on the shore. The only way to catch a Kelpie is to place a silver bridle on it, after which the Kelpie will be under your control.
They are extremely dangerous and should be avoided at all costs.