Good news for fans of hardcore sci-fi: Like the Alien series it’s kinda-sorta a prequel to, Ridley Scott’s Prometheus will be rated R, 20th Century Fox confirmed today. Bad news for those same fans: Guillermo Del Toro says Prometheus may have obviated his dream project, At the Mountains of Madness, another expensive R-rated sci-fi movie that has too much in common thematically with Scott’s film. Because Hollywood hates going to the same well too many times!