Trivia about Swamp Thing. * WILHELM SCREAM: Can be heard as Swamp Thing throws a thug out of his speed boat. * Dick Durock was forced into the role of the Swamp Thing by necessity. He'd been brought on board the project as a stuntman, but the filmmakers found that it was impossible to go from Durock to Ray Wise - who had been cast as Alec Holland, Swamp Thing's former self - and back again because the two men looked so different in Swamp Thing's makeup.