The kelpie, a water spirit in Scottish legends, lives in streams and rivers. Some sources say kelpies also haunt lakes and seas. The kelpie is a shape-shifter who can appear as a beautiful horse or a lovely woman. In her horse guise, she lures people onto her back, and then dives deep into the water, drowning the rider.
Kelpies warn of approaching tempests by wailing and howling, and continue their chilling cries throughout the storm.
One can only tame a kelpie by taking possession of its bridle. Then the kelpie must submit to the owner’s will. Kelpies are strong, and can do the work of ten horses. However, capturing and mastering a faerie spirit like a kelpie is a dangerous undertaking. I wouldn’t recommend it.