Sigfried Manheim is the main antagonist of Brian Henson's 2001 telefilm/mini-series Jack and the Beanstalk: The Real Story. He is the manager of a rich company and the boss of the protagonist Jack Robinson. Siggy encourages Jack to turn down the idea of a rich food supply and build a casino. He is the one who cuts down the beanstalk (made from the remaining magic bean that had landed on rock) when Jack has climbed up, and then believed Jack to be dead. He had known the truth of the Robinson curse all along and was entrusted to tell him about the treasures (the Golden Harp and the Goose that laid the golden eggs, which the giants needed to rejuvenate their world), but instead, he had encouraged him to stay single and think only about his work so that as soon as Jack died, Siggy would keep the company to himself. Eventually, the giants, who had come to kill Jack to end the curse (after his ancestor, the first Jack and the one from the real fairy tale who had killed the kindly giant Thunderdell), scared Siggy away when he tried to kill Jack and Thunderdell's adoptive daughter Ondine for taking the treasures. After Jack returns the treasures to the giants, a newspaper reveals that Siggy was taken to a mental hospital for claiming to have been hunted by giants.

Jon Voight played him in the film.