Undine

Undines are a category of elemental beings associated with water, stemming from the alchemical writings of Paracelsus. Later writers developed the undine into a water nymph in its own right, and it continues to live in modern literature and art through such adaptations as Friedrich de la Motte Fouqué's Undine (1811) and Hans Christian Andersen's "The Little Mermaid" (1837). (Wikipedia)