The Forgotten Girl by India Hill Brown

Ooh, spooky! Iris loves the snow. So she and her best friend go out and play in the snow at night. Iris makes a perfect snow angel…on top of a grave. Then a girl starts appearing at Iris’s window at night. She says she just wants to be Iris’s friend, but she might have more sinister in mind. This girl wants to be remembered, and she’ll go to terrible lengths to get there. The question is, would being forgotten make you forget yourself?