Guillermo del Toro has a habit of signing on for awesome-sounding projects that he either drops out of or that never get made at all. Either way, not a day goes by that we shouldn't all be mourning the fact that we're probably never going to get a del Toro-directed Justice League Dark movie.
Based on the comic/supernatural super-team of the same name, the film would have followed some of DC's more mystical heroes on an adventure that more than likely would have taken them to Hell. The team usually consists of folks such as John Constantine and Deadman, but according to del Toro, his version of the film would have featured less-seen DC mainstays such as Swamp Thing and Etrigan the Demon. During a recent Reddit AMA, del Toro explained that in his mind, those two are are core parts of DC's arcane trinity:
It's a WB property, I am not sure I can comment [on the project]. Suffice to say that Demon or Swamp Thing mean to me what Batman and Superman mean to most mortals - perhaps even more. [Swamp] / Abigal love was a great source of inspiration for me.
In 1985's Swamp Thing Annual #2, Swamp Thing ventures into Hell to save the soul of his frequent love interest Abigail Arcane. During his Orphean journey, Swamp Thing encounters a number of DC's other magical characters, such as Deadman, the Spectre, the Phantom Stranger and, of course, Etrigan. It's almost like the comic might have made for a fantastic movie in the hands of the right director - say, someone who knew a thing or two about humanising monstrous heroes.