In Clue, Colonel Mustard (Martin Mull) is a guest of Mr. Boddy’s who’s being blackmailed for war profiteering. It’s revealed that he made his money from selling stolen radios on the black market, as well as having an affair with one of Miss Scarlet’s escorts. In one of the endings, he killed a stranded motorist in the lounge with a wrench.

Miss Scarlet (Lesley Ann Warren) is a character from the board game, Clue. In the film adaptation, she is a socialite who runs an illegal escort service, for which she is being blackmailed by Mr. Boddy. In one of the ends, she killed the cop in the library with a lead pipe.

In Clue, Mrs. White (Madeline Kahn) is a “black widow” who had her husbands disappear or die mysteriously. She is a guest of Mr. Boddy’s, and is also being blackmailed by him. The maid had an affair with one of her husbands, so in one of the endings, she killed the maid in the billiard room with a rope.

In Clue, Mr. Green (Michael McKean) is a State Department employee and guest of Mr. Boddy. He is blackmailed for being gay, a secret which would cost him his job. In one of the endings, he is suspected of killing the singing telegram girl in the hall with the revolver. He ultimately reveals himself as an undercover FBI agent, who actually killed Mr. Boddy in the hall with the revolver.

In Clue, Professor Plum (Christopher Lloyd) is a former psychiatry professor with the World Health Organization who had his license revoked after having an affair with a female patient. He is a guest of Mr. Boddy’s and is being blackmailed for his indiscretions. In one of the endings, he killed Mr. Boddy in the hall with the candlestick.

In Clue, the Singing Telegram Girl (Jane Wiedlin) is a character who visits Mr. Boddy’s party to deliver a message, before being killed by one of the guests. She is later revealed to be a former patient and lover of Professor Plum’s.