Elf On The Shelf
I didn't know these creepy things existed until last year and now one has moved into my house. This is an Elf On The Shelf. It comes with a book too. I have not read that yet, so I don't know the true story of the Elf.
I guess you put it in different spots around the house and it watches your children and scares them into being good so they get presents for Christmas. It was a gift.