Preliminary Thriller Conventions Applied to a Trailer

The Babadook

At the beginning eerie music is played that provides a suspenseful atmosphere. The mother says to her child that "nothing bad will happen", which is quite misleading as later in the trailer we clearly see that the protagonist is in a great deal of danger. The boy mentions that three knocks symbolises that the Babadook is near, which then can be heard later in the trailer, creating a sense of mystery whether he is real or not. "Don't let him in" is repeated by the boy in a very distressed manor, which really builds up the tension of the trailer.