A kelph (pl. kelphs) is a supernatural water horse found in the Earth's oceans. They had close interaction with the sirens, akin to horses and humans. They can be easily frightened by non-aquatic peoples and animals, to the point of creating a large stampede of rushing water.
Kelphs take on the form of a tangible watery horse. How they manage to maintain a liquidous form remains uncertain, as none have been successfully captured for study other than the sirens. Even though they are susceptible to electricity, the remains of a kelph do not maintain its form, suggesting that kelphs can shapeshift.
They have been observed to gallop faster than typical horses, at least in a frightened state.