"'Feejee Mermaid' has become the generic term for the many fake mermaids that can be found around the world..."
This article contains information relating to a hoax. According to Cambridge dictionary a hoax is "a plan to deceive a large group of people; a trick."
A short article on the Hotheaded Naked Ice Borer first appeared in the April, 1995 issue of Discover magazine. The article was written by Tim Folger, then an editor at the magazine. Folger wrote several other April Fool stories for the magazine, including one about the discovery of prehistoric musical instruments—bagpipes, a mastodon-tusk tuba, and a bone triangle—supposedly used by Neanderthals.
The article carried a purported photo of a seal-like creature with a bony growth protruding from its head. A deputy art director created the "bony growth" by manipulating an image of a trilobite. According to the article, this animal had recently been discovered in Antarctica. The bony structure was suffused with tiny blood vessels that would heat it to a temperature high enough to melt through the ice. To acquire food, a group of these animals would burrow into the ice underneath suitable prey, and use their heads to melt through. When the animal, usually a penguin, sank helplessly into the water, the group of Borers would devour it. It was even speculated in the article that Antarctic explorer "Philippe Poisson" (poisson d'avril, "April fish," is the French equivalent of "April fool") may have been eaten by a group of these animals when he disappeared in 1837.
A clue that indicated that the Ice Borer story was a hoax can be found in the name of the biologist who discovered the animal, "Aprile Pazzo" ("April Fool" in Italian). Discover magazine received more mail about this article than about any other article it had ever published. A number of zoo officials and scientists sent humorous letters to the magazine asking how they could acquire specimens of the creature. Ripley's Believe It or Not! picked up the story and ran it as a real news item.