Guillermo Del Toro is known for making monster movies as well as having an affinity for Swamp Thing and characters of a similar manner.
Back in 2011 at the San Diego Comic-Con, Del Toro actually said he would love to do a Swamp Thing movie, that he "would love to do it, but that doesn't mean I am going to do it. I try to get involved with things that I love; we develop them, we write them and then it is up to the Studios to make them or not."
As Del Toro noted, it's up to the studios to make them or not, and now it's currently rumored that because of how well Pacific Rim is testing with audiences, Warner Bros. might be green lighting Guillermo Del Toro's Swamp Thing movie -- which includes an entire ensemble of "dark" DC Comics heroes.
Via Latino Review:
Called HEAVEN SENT he is combining all the magical beings from DC Comics in one epic adventure. Deadman, The Spectre, Swamp Thing, Constantine Hellblazer, Phantom Stranger, Zatanna, Zatara, and Sargon as well as Etrigan the Demon
[[wysiwyg_imageupload:3799:]]Latino Review does say that this is a ways off, so this could just be in the talking stages. The movie could follow the Justice League movie as well as the rumored Batman 2016 movie and DC Comics' other stable of movies with The Flash and Wonder Woman, in addition to the sequels for Man of Steel.
Many of the characters mentioned above are currently featured in the DC Comics comic book, Justice League Dark. Swamp Thing has his own solo book of the same name, which is written by Batman writer Scott Snyder, who will also be doing the Man of Steel comic book. The Spectre recently appeared for the first time in the pages of the Phantom Stranger, with Etrigan having his own series, Demon Knights.