Luke Lerner

Luke Lerner is the antagonist of the 2017 horror/comedy Better Watch Out directed by Chris Peckover.

He is portrayed by Levi Miller, who is mostly known for playing Peter Pan in the 2015 film Pan and playing Calvin O'Keefe in the upcoming film adaptation of A Wrinkle in Time.

Personality
Luke comes off as sweet and precocious to his parents and babysitter, a mischievous goofball with his best friend Garrett, but these are all ruses to hide his more sinister, manipulative, and abusive tendencies. Despite this, he is still a child at heart, finding great amusement in games like Truth or Dare or being fascinated by pot smoke appearing out of a stab wound that he caused.

Biography
Luke's parents are leaving the house to attend a Christmas party and is watched over by his longtime babysitter Ashley, whom he has a huge crush on. He is dismayed that she is moving to Pittsburgh in a couple of days and tries to hit on her that night, cuddling up to her while watching a movie and drinking champagne with her. Soon, people begin to terrorize them, calling them on the house phones and throwing a brick through a window. After the assailant breaks in, Luke retrieves his father's handgun and goes to confront the intruder, leading to him and Ashley hiding in his bedroom closet. However, she recognizes the mask the intruder wears as one that he owns, and she quickly realizes that the intruder was Luke's friend Garrett pranking her to get her to have stronger feelings for Luke. After she threatens to call his parents, he pushes her down the stairs and knocks her unconscious.

Ashley wakes up bound to a chair and gagged, getting molested by Luke in a game of Truth or Dare by him and Garrett. Her boyfriend, Ricky, whom she had an argument with and texted earlier, arrives to make amends to her, but he gets himself kidnapped as well. Luke then kills him with a paint can ala Home Alone to prove a point made about the fatality of being hit with a paint can to Garrett. Ashley manages to free herself and take Luke's father's pistol, but runs away after she realizes Luke hid the ammo. After a struggle with a still complicit Garrett, she is knocked unconscious by the brick used to break the window.

Waking up, she finds her entire body wrapped up in duct tape and Christmas lights, rendering another chance of escape impossible. As Luke lures and murders Ashley's ex-boyfriend Jeremy, Ashley convinces Garrett that Luke is a monster and gets him to free her. After getting her left arm and halfway up her body, Garrett is shot and killed by Luke's father's hunting shotgun. After spending another moment with Ashley, he stabs her in the neck and leaves her for dead before rigging the entire crime scene to imply that Jeremy was the killer.

His parents arrive home and discover the gruesome scene. He smiles, confident that he will get away with it, only to overhear paramedics wheel out a still alive Ashely, who used a piece of duct tape to seal her wound before she bled out. He then asks his mom to visit Ashley at the hospital, feigning concern for her well-being.