Samuel, The Babadook
In the Australian film The Babadook, a worn-out widow and her son Samuel live alone in peace. As the movie progresses, Samuel becomes fixated with a storybook character named Mister Babadook, throwing tantrums and developing seizures in response to the bedtime story. He builds weapons to fight the monster, much to his mother's distress. Samuel's behaviour does not come from mere growing pains. It turns out, in fact, that the Babadook is after the family.