Lady in the Water: I enjoyed this low key, modern and quirky fairy tale, critically underrated in my opinion. M. Night Shyamalan of The Sixth Sense, The Village, Signs, and more, produced this film with a hauntingly beautiful score by James Newton Howard. A Philadelphia apartment superintendent finds a strange girl in the swimming pool who he discovers is a water sprite from a bedtime story trying to find her way home. He tries to help her fight the evil creatures that are preventing her from returning to her water world while at the same time he deals with the eccentric tenants of the building complex.
Water sprites are creatures that inhabit ponds and fresh water springs etc. In Greek legend they were called naiads. The water nymph associated with particular springs was known all through Europe in places with no direct connection with Greece, surviving in the Celtic wells of northwest Europe that have been rededicated to Saints, and in the medieval Melusine. Another name for them was Undine.
In Finnish folklore there is Utuneito or mist maiden. Similar to Will o the Wisps they rose over lakes and ponds to sing and dance. Not all water spirits were good and in Slavic tales they could also be demons. There are also the shape shifting water spirits like the Nix, of Norse myth, who drew people to the banks of rivers with haunting songs or the Kelpies of Scottish fame who drowned their hapless victims.