Kelpie
Kelpie refers to a species of equine known to inhabit Equestria.
Biology
Three varieties or forms of Kelpie are known to exist. One is an aquatic, seahorse like creature, resembling the Aquastria breeds of Seaponies or Mermares and not possessing hooves. Others somewhat resemble Seaponies, with equine front parts and fish tails.
Other Kelpies known to inhabit Farasi are vastly different in appearance, instead resembling Earth Ponies but with bodies that are made out of water in various states.
Abilities
Some aquatic Kelpies possess magical voices capable of enchanting others in a similar fashion to Sirens.
Terrestrial Kelpies possess powers of hydrokinesis, allowing them to control and transform water, including that which makes up their bodies.
Known Kelpies
Behind the scenes
Kelpies are based on a mythological-and often malevolent-breed of horse. In the myths, Kelpies would lure unsuspecting travelers into their watery homes, only to drown them.