The story of an astrologer who claimed in a 1941 keynote address that the stars indicated Hitler would invade the United States from Brazil and eventually be defeated. The astrologer, Louis de Wohl, was actually an agent for the British government:

What no one realized was that de Wohl’s lecture was pure propaganda from the British government, which was attempting to drag the Roosevelt administration into WWII by any means necessary. De Wohl, who was employed by SOE (Special Operations Executive, the wartime sabotage unit), had been dispatched with instructions to present himself as a renowned astrologer with no connections to Britain, and to undermine America’s belief in the invincibility of Hitler. As the spy novelist William Boyd put it in a 2008 radio interview: ‘At the time, there was a perception of American people, in the minds of the British Security Services, that they were more gullible than us Brits.’

“The Inconvenient Astrologer Of MI5.” — Emma Garman, The Awl

See also: “CIA Divorces: The Secrecy When Spies Split.” — Ian Shapira, Washington Post