 Veteran character actor Martin Mull is dead. The hip sensation in the 1970s was 80 years old. ABC's Aika Jachi looks back. Comedian and actor Martin Mull appeared in nearly 40 films and more than 50 shows. From the boss of the titular character Roseanne to the private eye in Arrested Development and the vice principal of Sabrina the Teenage Witch. But perhaps most known for his role as Colonel Mustard in the murder mystery Clue. I can't take any more scares.