The Creature of the Black Lagoon (aka The Gill-man) is the main monster character of Creature from the Black Lagoon, the 1954 science fiction horror film and its sequels. It has also made appearances in movies such as The Monster Squad (1987) and as a background character in Monster High as the father of Lagoona Blue. Due to its stature as one of Universal Studio's famed monsters, it has made a wide number of cameo appearances in media across the board over the 60+ years since its debut.
The origin of the Gill-men is nebulous at best, with two possible theories known. The first and most widespread theory, as proposed by Dr. Thompson, is that the Gill-man discovered in 1954 was the last surviving member of a species that evolved during the Devonian Age and by the modern age was only found in the Black Lagoon, located deep in a previously hitherto unexplored Amazon Rainforest. These creatures were descended from an extraterrestrial race that had visited the planet Earth during those early years. Another theory is that the creature is the result of severe pollutants into the Amazon by a pharmaceutical corporation, who had been exploiting the rainforest.
The creatures of such a man-fish were known to the local native tribes.