who did the demon voice in the exorcist
Mercedes McCambridge Carlotta Mercedes Agnes McCambridge[2] (March 16, 1916 â€“ March 2, 2004) was an American actress of radio, stage, film, and television. Orson Welles called her "the world's greatest living radio actress."[3] She won an Academy Award for Best Supporting Actress for All the King's Men (1949) and was nominated in the same category for Giant (1956). She also provided the voice of 'The Demon' in The Exorcist (1973).