A complete waste of time!! This movie is neither scary nor logical.
A widow and her 5 year old son are tormented by an evil entity (The Babadook) that was summoned when she read her child a story book about the character. Somehow she manages to trap it in the basement where she keeps it chained and feeds it worms to keep it happy.
I wish there was more to this movie than I described, but there just isn't.