Fiction as Truth
In 1938, the Orson Welles' radio broadcast of the sci-fi fantasy "War of the Worlds" about aliens invading earth caused a nationwide panic.
In Poe's case the public was prepared to accept the idea of performing surgeries using hypnotism as an anesthetic, a commonly reported phenomenon (albeit untrue). "War of the Worlds" played on the scientific explanation of a crowded universe where sentient alien beings living on Mars.
Have you ever read a fictional work that you thought was true? Why did you believe it was true and what did it cause you to do?