Aughisky

An aughisky is an exceedingly rare creature that takes the form of a beautiful-looking horse.

Ecology
It wanders dry land looking for humanoid prey. Once it finds a suitable meal it tries to make itself appear that it would be easy enough for its prey to ride it. If it takes the bait, the prey will find itself stuck to the aughisky's flesh. The aughisky will then gallop as fast as it can back to the waters where it makes its home. It will drown the trapped humanoid and then devour the corpse, leaving only the creature's liver which is often found washed up on the shore.