A Rusalka is a being from Slavic mythology and folklore that is considered a water-demon that haunts waterways - according to most traditions the Rusalki were fish-women, who lived at the bottom of rivers. In the middle of the night, they would walk out to the bank and dance in meadows. If they saw handsome men, they would fascinate them with songs and dancing, mesmerize them, then lead the man away to the river floor to his death.

In most versions of the myth Rusalka are the restless souls of women who have died before their time and although dangerous to humans can be granted peace if their original deaths are somehow avenged.