In Celtic mythology, the water horse is a significant creature often symbolizing both danger and enchantment. Known as the selkie or kelpie, it can transform from a horse to a human. These beings are associated with water and represent the duality of attraction and peril. They embody themes of transformation and the unpredictability of nature, illustrating the belief that water can be both a source of life and a force of destruction. The water horse serves as a cautionary figure in many tales.