I got a book from a scholastic book fair back in the 1990s. It was about a girl who lived in a house with her baby brother (maybe sister). There was a creature in the woods who stole the baby and she had to rescue him/her. The cover was terrifying (at least to 11 year old me) and I even bought it twice because the cover came off of one.

This creature was maybe a witch or something that needed the youth of the baby to survive – it fed off of the baby or something like that. The book would probably have been written between 1985 and 1995, young adult thriller/horror/fantasy.

Any help is appreciated!!!