There was a book that I read in the early 1970s about a girl (A) whose family took in another girl (B), I can’t remember why. Girl B turned out to have powers that she used against Girl A. I remember two scenes. Girl A was going to the prom or a big dance with her boyfriend and was going to make her own dress. Girl B “made” Girl A buy a pattern and color for a dress that was unbecoming to Girl A. Also, Girl B “made” Girl A sick right before the dance so Girl B went with Girl A’s boyfriend. I don’t remember how Girl A got rid of Girl B, but the book ends with Girl A saying whenever she reads a story in the newspaper about a wife dying, or an accident with 3 people where the woman dies, that she wonders if it is Girl B is still out there up to her old tricks.