In 1842, P.T. Barnum told the press that he'd found, and would exhibit, a mermaid. According to Barnum, a man named Dr. J. Griffin had arrived in New York with a real mermaid he'd discovered near the Feejee Islands. Since Barnum had informed the press in advance, crowds of people came to the exhibit to take a look at the real live mermaid. What they saw was nothing like the beautiful half-woman, half-fish creatures they'd heard about. What they saw wasn't even alive. The Feejee Mermaid was nothing more than the top half of a mummified monkey sewn onto the tail of a fish.

In fact, "Dr. J. Griffin" was Levi Lyman, Barnum's accomplice in the deception. Dr. Griffin even gave a lecture about the veracity of mermaids at the exhibit. According to the Museum of Hoaxes, Griffin claimed that "mermaids must be real since all things on land have their counterpart in the ocean — sea-horses, sea-lions, sea-dogs, etc. So therefore, we should assume there are also sea-humans!" Despite the obvious hoax, throngs of people kept coming to the exhibit.