Swamp Thing (Alan Moore)

In 'The Anatomy Lesson' (Swamp Thing #21, 1984), Moore revealed that Alec Holland had never truly been transformed into Swamp Thing—Swamp Thing was actually a plant elemental that had merely absorbed Holland's memories and consciousness, believing itself to be him. This redefinition fundamentally changed the character's mythology and opened the door for Moore's exploration of ecological, philosophical, and horror themes.

Alan Moore wrote Swamp Thing from issue #20 through issue #64, published from 1984 to 1987. The run was originally part of DC Comics' main line but helped inspire the creation of the Vertigo mature-readers imprint in 1993, and artists on Moore's run included Stephen Bissette, John Totleben, and Rick Veitch.

John Constantine, the Liverpool-born occult detective, was introduced in Swamp Thing #37 (1985) as a mysterious figure who guides Swamp Thing through supernatural crises. Constantine later received his own ongoing series, 'John Constantine, Hellblazer,' which became one of the longest-running titles under DC's Vertigo imprint.

Moore's run is credited with introducing serious literary and horror sensibilities to mainstream American superhero comics, tackling themes including environmentalism, identity, sexuality, and mortality in ways mainstream comics had rarely attempted. It is widely considered one of the foundational works that led to the creation of DC's Vertigo imprint and the broader acceptance of mature comics in the 1980s and 1990s.