Swamp Thing, a fictional character, is a plant elemental in the DC Comics Universe created by Len Wein and Berni Wrightson. He first appeared in House of Secrets #92 (July 1971) in a stand-alone horror story set in the early 20th century (written by Wein and drawn by Wrightson). The Swamp Thing then returned in his own series, set in the contemporary world and in the general DC continuity. The character is a humanoid mass of vegetable matter who fights to protect his swamp home, the environment in general, and humanity from various supernatural or terrorist threats.
The character found perhaps his greatest popularity during the 1980s and early '90s. Outside of an extensive comic book history, the Swamp Thing property has inspired two theatrical films, a live-action television series, and a five-part animated series among other media.
The Swamp Thing character first appeared in House of Secrets #92 (June–July 1971), with the name Alex Olsen. The comic is set in the early 20th century, when scientist Alex Olsen is caught in a lab explosion caused by his co-worker, Damian Ridge, who intended to kill him to gain the hand of Olsen's wife Linda. Olsen is physically altered by chemicals and the forces within the swamp. He changes into a monstrous creature who kills Ridge before the latter can murder Linda, who has started to suspect Damian. Unable to make Linda realize his true identity, the Swamp Thing sadly ambles to his boggy home.
After the success of the short story in the House of Secrets comic, the original creators were asked to write an ongoing series, depicting a more heroic, more contemporary creature. In Swamp Thing #1 (October–November 1972) Wein and Wrightson updated the time frame to the 1970s and featured a new version character: Alec Holland, a scientist working in the Louisiana swamps on a secret bio-restorative formula "that can make forests out of deserts". Holland is killed by a bomb planted by agents of the mysterious Mr. E (Nathan Ellery), who wants the formula. Splashed with burning chemicals in the massive fire, Holland runs from the lab and falls into the muck-filled swamp, after which a creature resembling a humanoid plant appears some time later. Roy Thomas and Gerry Conway, who co-created Man-Thing for Marvel Comics a year and a half earlier, thought that this origin was too similar to that of their character, and Wein himself had written a Man-Thing story (in fact, the second) that was published with a June 1972 cover date, but he refused to change the origin in spite of some cajoling by Conway, who was his roommate at the time. Marvel, however, never took the issue to court, realizing the similarity of both characters to The Heap.
The creature, called Swamp Thing, was originally conceived as Alec Holland mutating into a vegetable-like creature, a "muck-encrusted mockery of a man". However, under writer Alan Moore, Swamp Thing was reinvented as an elemental entity created upon the death of Alec Holland, having somehow absorbed Holland's memory and personality into itself. He is described as "a plant that thought it was Alec Holland, a plant that was trying its level best to be Alec Holland." This in turn further diverged the character from Marvel's character, although creatures resembling the Man-Thing likeness appeared in the Parliament of Trees. This was Alan Moore's second re-invention of a comic book character, the first being Miracleman.
The major difference between the first and second Swamp Thing is that the latter appears more muscular than shambling, and possesses the power of speech. Being able to speak only with great difficulty, Alex Olsen's speech impediment is a major reason why his wife could not recognize him. In Swamp Thing #33, Alan Moore attempted to reconcile the two versions of Swamp Thing with the revelation that there have been many previous incarnations of Swamp Thing prior to the death and "rebirth" of the Alec Holland incarnation. Three others are notable: Albert Höllerer, a pilot in World War II, appeared briefly and had his story summarized in Swamp Thing #47 (May 1986), and Aaron Hayley appeared in the Swamp Thing: Roots graphic novel (1998) set in the 1940s, and Alan Hallman, the Swamp Thing of the 1950s and 1960s, introduced in Vol. 2 #102 (December 1990) and eventually, after being corrupted by the Gray, killed by Holland. As a result, Holland is known as Swamp Thing IV by the editors of the DCU Guide. The principal two Swamp Things are also connected in that Holland's first wife is Linda Ridge, a descendant of Damian Ridge.
* Swamp Thing's expansion into media outside of comic books began with his first eponymous film in 1982. Directed by Wes Craven, it starred actor/stuntman Dick Durock as the title character and the superhot Adrienne Barbeau as its barely dressed love interest.
* A sequel, The Return of Swamp Thing, was produced in 1989. This was much lower in budget and met with significantly less success than its predecessor.
* The aforementioned film series rejected the popular Alan Moore revision of Swamp Thing's origin and portrayed Swamp Thing with his original origin as a man turned into a plant-like entity. They also heavily featured Anton Arcane, who now became the man responsible for causing Alec Holland's transformation into Swamp Thing.
* The documentary feature film The Mindscape of Alan Moore contains a psychedelic animation piece based on the "Love and Death" issue of Swamp Thing.