In the latest season of the hit Netflix sci-fi series, Bower plays Peter Ballard (AKA Henry Creel and One), who transforms into the monster Vecna.
  
Speaking to The Hollywood Reporter, Bower was asked whether his
    co-stars were frightened of him on set, and he singled out the reaction of
    Eleven actor Millie Bobby Brown.
“Millie. She was terrified,
    absolutely terrified,” he said. “She’s a very open, receptive individual as
    a soul. I’ve become very friendly with her parents, too, and her mom finds
    it hilarious. 
  
“Every time I see her, she will say, ‘Millie thought you were
    so scary! She’d call me. She was in tears. She said, ‘Jamie wasn’t there
    anymore!’”
Bower has been defended by fans for his approach to
    acting on the series, with some describing the process as “method acting
    done right”.
  
In the same interview, he also described other instances in
    which co-stars were scared of him. “I remember the boy that plays Fred in
    episode two, he was very spooked,” said Bower.
“He found it
    scary. And the poor actress who plays Chrissy. The Chrissy kill was my first
    day on the job and I would be talking to myself in the house; she’d be in
    the hall and I’d be in the bathroom calling out her name, and she was really
    spooked. Also, we filmed that at four in the morning, which doesn’t help!
    That’s scary for anyone.”