One of the more intriguing elements of "Green Lantern" will be acclaimed actor Peter Skarsgard's turn as the sympathetic villain Hector Hammond.  One of Green Lantern's greatest nemesises, Hammond won't have the insanely gigantic head he has in the comic book, but Skarsgard did undergo a five hour make up job to appear as though his head has bizarrely mutated.

In the movie, Hammond is an average college professor and former childhood friend of both Jordan and Carol Ferris who happens to be an expert in the study of alien life forms.  When his father, a U.S. Senator played by Tim Robbins, uses his connections to get him access to the recovered body of Abin Sur, Hammond investigates only to be infected by Parallax. This causes his head to grow unproportionately and quite disgustingly, but it also gives him new abilities such as telekinesis as well as a less friendly personality.  Production Designer Grant Major also notes, "He channels this Parallax thing in deep space and there is a telepathic connection between the two" and that eventually "He's fighting with his [infected state] and his original personality."

Director Martin Campbell doesn't see Hammond as a villain, but rather a victim of circumstance.

"If someone like Hector Hammond is infected and turns into [a powerful creature] there is a certain pathos and a certain sympathy you have for him," Campbell says. "You have to make these characters human. They just can't be black and white and just evil. They've got to have personalities and they have to have character."