Wikipedia
Boginki
The Boginki (Polish for "Little Goddesses"; singular: boginka) are spirits in Polish mythology. Traditionally, covens of old women would perform sacrifices and rituals for the nymphs of the riverbanks. Boginki were said to steal babies from their human parents that were replaced with Odmience – the changelings. These spirits are said to be the original deities of life and predate the sky gods. They also appear to be forerunners of the Rusalki.