Mulder of 'The X-Files' is Fox Mulder, an FBI special AGENT played by David Duchovny in the science fiction television series. He is a believer in the paranormal and conspiracy theories, and his investigations often involve supernatural phenomena. He is partnered with Dana Scully, a medical doctor and skeptic, who serves as a foil to his beliefs. Together they investigate unsolved cases, known as X-Files, which often involve paranormal elements.