Since 2016, Thomas has worked frequently with filmmaker Mike Flanagan, appearing in his films Ouija: Origin of Evil, Gerald's Game and Doctor Sleep, as well as in the Netflix horror series The Haunting of Hill House, which Flanagan created and directed. Thomas also has a role in Flanagan's follow up to The Haunting of Hill House, The Haunting of Bly Manor, and Flanagan's mini-series Midnight Mass.
