The titular monster from the 2008 movie Swamp Devil. When in human form, he uses the name Jimmy Fuller and is portrayed by Nicholas Wright.
He appears a mass of plants with eyes and a nose.
He can transform between his human and true form at will. His human form can presumably look however he wants it to as when Melanie's father Howard was about 20 years old Jimmy murdered at little girl. Present day Howard is portrayed by Bruce Dern making Jimmy much older than his human form. He can also grow and shrink his plant body.
When Howard Blaime (Marc V. Denis) was 20 years old, a little girl (Jenna Wheeler-Hughes) was murdered in a swamp near the town of Gibbington. Around half a century later Howard (now portrayed by Bruce Dern) is the retired sheriff and when the murders restart, he takes the blame. A man named Jimmy Fuller (Nicholas Wright) calls Howard's daughter Melanie (Cindy Sampson) back to the town to clear the former sheriff's name. The current sheriff Nelson Bois (James Kidnie) believes Howard is the murderer. After many people including Nelson and a man named Bigg (Kwasi Songui) are killed, Howard and Melanie learn that Jimmy is really a swamp monster and the true murderer. After figuring out that he can't go past the Gibbington sign, Howard, Melanie and Deputy Jolene Harris (Allison Graham) devise a plan to destroy him. Melanie and Jolene get in a police car and have Jimmy chase them out of town. They turn around and at the same time Howard gets in his truck and starts driving. As Jimmy is staring as Melanie and Jolene they drive past him and he turns around only to find out that Howard is about to hit him. As Jimmy prepares to stop the truck, Howard hits the gas, says to Jimmy "You are now leaving Gibbington", rams him with truck, sending him flying past the Gibbington sign causing him to explode.