In A Monster Calls a young boy named Conor (Lewis MacDougall) makes friends with a mysterious being that looks like a giant tree.
That “monster,” played by Liam Neeson, then guides Conor as he copes with the illness of his mother (Rogue One’s Felicity Jones) and strict rule of his grandmother (Sigourney Weaver).
Being a central figure in the film, he gets a lot of screen time. And being a walking bundle of roots, he had to be created almost entirely with practical effects and CGI.
“I was involved with the motion capture for essentially two weeks,” Neeson says, “and most of my scenes were acting with Lewis.”