Down and Dirty Duck, first shown under the abbreviated titles Cheap! and Dirty Duck, is a 1974 American adult animated comedy film written and directed by Charles Swenson and starring Mark Volman and Howard Kaylan (Flo & Eddie) as the voices of a strait-laced, low-level white-collar worker named Willard and an unnamed duck, among other characters. The plot consists of a series of often abstract sequences, including plot material created by stars Kaylan, Volman, Robert Ridgely, and, according to the film's ending credits, various people Swenson encountered during the making of the film. The film received mostly negative reviews and became relegated to late shows.

Willard Isenbaum, a lonely insurance man with wild sexual fantasies, decides to propose to the new secretary, Susie, whom he has only known for a day and to whom he has never spoken. He spends the entire morning before work fantasizing about having sex with her, but his attempts to approach her fail. His female boss sends him to investigate a claim filed by Painless Martha, an aging tattoo artist, who works in the city. Martha believes in a Ouija board message saying that she will be "killed by a bomb delivered by a wizard on Tuesday".

When Willard tells her that the insurance company will not pay until her death, she dies of a heart attack [after an explosion noise]. Her will stipulates that her killer must take care of her duck. After the duo spend a night in jail, the duck takes Willard to a brothel. After a wild night of partying, they wind up in the desert, where the duck dresses Willard in women's clothing in an attempt to get a ride. After several encounters with an old prospector dying of thirst, a racist police officer, a lesbian couple, and a short Mexican "bandito", they are finally picked up by a trucker.

Back at his apartment, Willard creates a makeshift sex object, which the duck eats. Shortly after, Willard discovers that the duck is female, and has sex with her. The following morning, Willard and the duck go to Willard's job, where Willard has sex with his female boss and quits his job shortly after. Willard and the duck leave, and the movie ends with Willard saying that the duck was a good duck after all.

After the release and success of Fritz the Cat, several animated films meant for adults rather than children enjoyed success. Fritz, a film based on a character created by artist and illustrator Robert Crumb, was the first animated movie to receive an X rating in the United States. Charles Swenson developed Down and Dirty Duck as a project for former Turtles and Mothers of Invention band members Kaylan and Volman under the title Cheap!

Producer Jerry D. Good pitched the film to Howard Kaylan and Mark Volman while the production company, Murakami-Wolf, prepared the animated sequence for Frank Zappa's 200 Motels. Kaylan and Volman met with director Charles Swenson on June 7, 1973; Swenson had written the screenplay for Kaylan and Volman under the title Cheap!

The film's production budget was $110,000. According to Swenson, he created almost all of the animation himself, although publicity attributed the animation work to the Murakami-Wolf Production Company, with Academy Award Winning animator Fred Wolf, credited as his son's name, Bill Wolf, helped animate parts of the film personally.

Kaylan and Volman recorded the music at Cherokee Studios with The Robbs serving as their backing band, credited as Flo & Eddie.