This story consists almost entirely of "Prometheus" spoilers.

You've been warned.

True to his legacy of sci-fi-horror, Ridley Scott peppered "Prometheus" with moments that are sure to make you wish you'd kept your helmet on, but none of the film's shocking moments even approach one hair-raiser in particular.

The sequence doesn't require much identification beyond "that scene," but in case you've already repressed the memory of it, here's a refresher.

Hours after an intimate encounter with her alien-infected boyfriend, the supposedly infertile Elizabeth Shaw (Noomi Rapace) finds out that she is, in fact, three months pregnant with something. Shaw, desperate to get the thing out of her, undergoes an impromptu Cesarean section in a futuristic self-surgery med-pod.

Now you remember.

We spoke with co-writer Damon Lindelof about the genesis of that sequence and why it works so well at creeping the hell out of everyone.

Lindelof was quick to praise the sequence, but he almost as quickly shifted the credit to his co-writer. "The first thing, it's one of my favorite scenes in the movie, certainly on an action level. It's the most frightening and disturbing scene in the movie by far," he said. "The second thing, this was Jon Spaihts' idea."

Spaihts wrote the initial draft of "Prometheus," which tied the story closer to the other films in the universe, as apparent in the scene's original version. "In Jon's draft, essentially Shaw gets a facehugger on her and gets implanted with a xenomorph, a traditional chest burster, so she used the med-pod to essentially extract this thing from her chest," Lindelof said.

So when he took a crack at the scene, Lindelof decided to relocate the foreign body to Shaw's abdomen. "I thought it was an amazing sequence, but I said, 'I think this scene is going to be even more upsetting and disturbing if it plays into the fertility and sexual aspects of the "Alien" universe,' " he said. "So things were rejiggered so that Holloway eventually impregnates Shaw, who is infertile, with his now enhanced or corrupted, depending on which way you look at it — I won't confirm either here — DNA, so this is literally a fetus. It's a child. The fact that she is pregnant was what I brought to it, and that was my story contribution to that sequence."

Then there was the actual performance, for which credit can only be given to Rapace. "Obviously Noomi was on that set for a couple days and the emotional intensity that she brought to what is intentionally an absurd sci-fi scenario — it really feels real and gritty and grounded and horrifying. I think she brought it to life," he said.

But even with Lindelof and Spaihts both providing the ingredients for the scene, Lindelof gives most of the credit to Scott. "Ridley, from the choreography of what the med-pod itself is doing — in terms of cutting her open and stapling her shut and removing this thing — what he shot practically versus what he did CGI and the answer is 'very little,' " Lindelof said. "The majority of that scene is practical, minus her stomach actually being opened up with a laser beam and seeing her internal organs. Most of that stuff was done practical, which is very rare these days."

For Lindelof, Scott's treatment of the scene harkens back to the most iconic scene from "Alien," in a good way. "Kudos to [Scott]. Even the idea of trying to step up to and/or approach the John Hurt scene from the original film and say, 'I want to do something that is as psychologically upsetting as that. It will be different, but let's not try to repeat myself, but at the same time honor that,' I think that he accomplished that and then some."

Check out everything we've got on "Prometheus."

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