Source: geekhardshow.com

8. Swamp-Thing Ain’t No Man

The Original Story: Alec Holland, plant scientist, was working with his wife on a new chemical solution. But Holland had a devious co-worker who wanted Alec's wife all to himself. Said co-worker blew Alec up, and sent his burned and charred body deep into the swamp.

What emerged, changed and mutated by the chemicals and the natural world, was the Swamp-Thing, a monster that was part man, part plant. The Swamp-Thing fought for the side of good for years after, but as a hideous monster that no one understood.

The Retcon: Alan Moore has some kooky ideas. Sometimes they work, sometimes they don't, but this one was a most certain hit. In one of the first issues of his landmark run on the character, The Anatomy Lesson, Swamp-Thing learned that he wasn’t Alec Holland. Instead, he was a plant elemental that was brought to life by Holland's death and imbued with his memories. He was a plant that thought it was Alec Holland.

This added a new layer of tragedy to Swamp-Thing, and provided new directions for the stories to take. If he really was all plant, he could do many additional things.