Swamp monsters have been a staple of fantastic fiction for years.
Swamp monster Wikipedia
Swamp creatures are humanoid creatures similar to fish or resembling living piles of swamp mire. They live underwater and occasionally come to the surface, but only when provoked. Within modern American folk myth and legend a notable example is Louisiana's Honey Island Swamp monster. Another notable example is the May River Swamp Creature that along with other rare and spectacular creatures occupies the marshes and supralittoral zones of the South Carolina lowcountry, near Bluffton, SC.
They seem to be akin to Kelpies, Kappa, the Loch Ness Monster, and muck monsters. Being only part humanoid, it is not popular belief that they are capable of speech, but in some cases, they have been capable of speech.
Popular renditions of swamp creatures occur in popular media such as comic books (Marvel's Man-Thing and DC's Swamp Thing). They have also been featured on older films, most notably The Creature from the Black Lagoon. In all these cases, they displayed superstrength, extreme underwater adaptability, possible muck spitting and a frighteningly bad attitude.
From the 1940s to the present many swamp monsters have been used in comics, an early example being Hillman Publications' The Heap.
Afterwards both DC Comics and Marvel created similar characters:DC had Swamp Thing, created by Len Wein and Berni Wrightson.
Marvel had Man-Thing, created by Stan Lee, Gray Morrow, Roy Thomas, and Gerry Conway.
The debuts of the two characters were so close that it is impossible to say which came first. Alan Moore, who worked on Swamp Thing for a period, later described the character's original incarnation as "a regurgitation of Hillman Comics' The Heap", adding that "When I took over that character at Len Wein's suggestion, I did my best to make it an original character that didn't owe a huge debt to previously existing swamp monsters."
Other swamp monsters in comics include:Solomon Grundy, created by Alfred Bester and Paul Reinman for DC Comics
The Glob, created by Roy Thomas and Herb Trimpe for Marvel Comics
Swamp Beast, from Monster in My Pocket by Dwayne McDuffie and Gil Kane for Harvey Comics.
Bog Swamp Demon, a fictional character appearing in Teenage Mutant Ninja Turtles comic books.
Danny Dunn and the Swamp Monster by Raymond Abrashkin and Jay Williams.
In the anime and manga Princess Resurrection, the characters are attacked by a tribe of monsters resembling the creature while vacationing by a lagoon, who desire Hime's blood to make them immortal and keep their kind from dying out. In a possible reference to the novel version of the movie, one of the creatures is roughly 30 feet tall.
In the anime and manga One Piece, the crew is attacked by Caribou who has eaten the Swamp Swamp Fruit (a Logia-type Devil Fruit that lets it's consumer turn into a "swamp").
The title creature in Theodore Sturgeon's 1940 short story "It!" is the earliest example of a plant-based swamp monster.
The Gill-man from the 1954 film, The Creature from the Black Lagoon appears as a fish-like humanoid.
A creature, credited as the Gill Man, also appears in the non-Universal release The Monster Squad (1987) along with Count Dracula, Frankenstein's Monster, the mummy, and the Wolf Man. He was portrayed by Tom Woodruff, Jr.
The episode "Heir Scare" of the Hanna-Barbera cartoon The Funky Phantom features a "Marsh Monster," a humanoid figure covered in hanging vegetation, described as having been a man once lost in the marshes. As might be expected, it turns out to be a costumed person with this one being a look-a-like of the Conway fortune's heir that was in cahoots with some servants.
An episode of Kolchak: The Night Stalker entitled "The Spanish Moss Murders" (December 6, 1974) features a young man, subject of a study in sleep research, whose nightmares of a Spanish moss-covered swamp-dwelling monster called Pèremalfait from stories heard in his youth in the Louisiana Bayou come to life. (The creature in this case was played by Richard Kiel.)
The DC comics character "Swamp Thing" mentioned above was the subject of a 1982 film and a a 1990 live-action television series.
In the 1986 novel It by Stephen King, It takes the form of a swamp monster to kill Eddie Corcoran.
The 1996 Goosebumps book "How to Kill a Monster" featured a Swamp Monster. It was depicted as a green-furred monster with the head of an alligator and a gorilla-like body.
The Swamp Monster makes an appearance in the 2015 Goosebumps movie performed by Nate Andrade (who was credited as "Monster #1"). He is one of Slappy the Dummy's monster and villain henchmen and is referred to as the "Bog Monster" during the 2014 Comic Con appearance. Its appearance is different where it looks like a giant creature made of moss.
The TV series Family Guy featured some swamp monsters. In the episode "I Never Met the Dead Man" (April 11, 1999), the Griffin family catches a creature strongly resembling a "Swamp Monster" while fishing. In the episode "Business Guy" (December 13, 2009), Carter Pewterschmidt and Lois Griffin trick Peter Griffin into surrendering Pewterschmidt Industries by scaring him into believing a local swamp monster will eat him if he does not. A seemingly real swamp monster scares Peter out of the office and then chases Lois and a disguised Carter before being trapped and unmasked to be Gregory House.
In The Simpsons episode "There's Something about Marrying" (February 20, 2005), Bart and Milhouse play various pranks on a Huell Howser look-alike. One of them is where they go fishing in a lake contaminated by the power plant, and the look-alike gets attacked by a Swamp Monster, which originally seemed like Blinky, the oft-referenced three-eyed fish.
A lake-dwelling merman by the name of Old Gregg makes several appearances on the 2004-2007 BBC television comedy The Mighty Boosh.
Victor Crowley is a deformed killer and main character in Adam Green's 2006 film, Hatchet.
David Winning's 2008 film Swamp Devil stars Bruce Dern as a retired sheriff trying to prove the existence of a swamp monster.
In Animal Planet's Lost Tapes, the episode "Swamp Creature" (January 26, 2009) is about the Louisiana Swamp Monster, which is said to be an abandoned Native American child who was raised by alligators.
While criticizing a movie featuring a Swamp Monster, one of the hosts of the 2010 series This Movie Sucks! (Ron Sparks) tells the legend of Lake Erie Pete about a man who becomes a crime-fighting swamp monster after his parents are killed by one.
Luke Harper, a pro wrestler in the Wyatt Family, has been called a swamp monster.
In Season Two of Scream Queens, the Green Meanie is described to be a swamp monster that lives in a toxic swamp near the C.U.R.E. Institute Hospital.
In 2015, the Impractical Jokers presented the "Bog Monster of Louisiana".