Dr. Philbert Mathias (portrayed by Michael Hitchcock) was a minor character in the 2005 sci-fi film Serenity. He was responsible for experimenting on River Tam for many years until she was rescued by her brother Simon. His inability to prevent her liberation would ultimately come back to bite him when the Union of Allied Planets sent an Operative to question him.
While reviewing recordings of Mathias' sessions with River, the Operative discovered that members of the Alliance Parliament had witnessed the experiments, thus it was possible that River's psychic abilities allowed her to glean classified secrets from them. Disappointed by the doctor's ineptitude, the Operative killed him by forcing Mathias to fall on his sword, talking to him the entire time.