With writer Len Wein, Wrightson co-created the muck creature Swamp Thing in "House of Secrets" #92 (July 1971) in a standalone horror story set in the Victorian era. Wein later recounted how Wrightson became involved with the story: "Bernie Wrightson had just broken up with a girlfriend, and we were sitting in my car just talking about life – all the important things to do when you're 19 and 20 years old. ["Laughs"] And I said, 'You know, I just wrote a story that actually kind of feels like the way you feel now.' I told him about Swamp Thing, and he said, 'I gotta draw that.'"