|"'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."
The Diplocaulus is an extinct genus of lepospondyl salamanders known to have lived between the Early to Late Permian Period (between 298.9 - 252.17 MYA), that have been allegedly filmed on a few occasions.
Professor Patrick Schembri of the Department of Biology at the University of Malta discussed the photos in an article that was published in November 2004 in the Malta Times. He identified the creature as an amphibian called a Diplocaulus, but he asserted that the photos had to be fake because the Diplocaulus had been extinct for 270 million years. He speculated that the creature was a model.
The image was later traced back to an amateur Japanese model-maker who had taken the photo back in 1992 and submitted it to a magazine as part of a contest.
Another sighting shows a pink diplocaulus in a lake. It moves, though not much. It has not debunked, though obviously, it may still be a hoax.