You are hereAughisky
These are the water horses of Ireland and are similar to the Each Uisge and Cabyll-Ushtey. They gallop out of the crashing waves up onto the shore, venturing inland. They are supposed to make excellent mounts for whoever can catch one but riding a Aughisky is not without risk. If they hear or see the sea they set off in an uncontrollable charge, galloping straight back into the water depths where they came from, taking their helpless rider with them to be torn apart.