Philip (Dethras)
From Tardis Wiki, the free Doctor Who reference
Philip was member of a British submarine crew during World War II. He was married in 1939. He knew some information about the Xankari which he shouldn't. He transformed into a creature that attacked the ship. This was because he was one of Dethras' experiments. He developed telepathy through close contact with the Fourth Doctor. (AUDIO: Dethras)