Rusalka

In Slavic mythology, a rusalka (plural: rusalki or rusalky) is a female ghost, water nymph, succubus, or mermaid-like demon that dwelt in a waterway.

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 them away to the river floor to their death.