A Monster Calls -- movie from the book by the same name.

This is an allegory about life and death. It is a beautifully told story. Bring tissues.

The opening narration explains much: "It begins like so many stories. With a boy, too old to be a kid. Too young to be a man. And a nightmare."

Twelve-year-old Conor O'Malley must face his mother's terminal cancer, his strict grandmother, his estranged father, and his school bully, Harry. One night at 12:07 a.m., Conor is visited by the tree-like Monster, who tells Conor it has come to tell him three true stories, after which Conor must tell the Monster his own story: the truth behind his nightmare.

The thing about stories like this is the same as Mary Shelly's Frankenstine. by the end of the story, you will discover that the Monster isn't the non-human thing. it's someone else. as Humans can be more monstrous than monsters themselves... (and the monster union is complaining, let me tell ya

The monster, in this case, was the truth behind Connor's nightmares.