It's looking like even more awesome stuff was eventually cut from the final version of Prometheus. As screenwriter Jon Spaihts tells Empire. The major one revealed by Jon is that the facehuggers were going to factor heavily into the plot of the film. Holloway getting himself facehugged during the exploration of the planet along with David purposely infecting Shaw with a xenomorph. It's likely this stuff was being held back for the sequel Paradise which hasn't been officially given a release date yet.
"I did have facehuggers in my original draft," says Spaights. "David, as he began to get fascinated by the science of the Engineers, doesn't deliberately contaminate Holloway with a drop of black liquid. Instead, Holloway hubristically removes his helmet in the chamber, is knocked unconscious, facehugged and wakes up not knowing what had been done to him, and stumbles back into the ship."
"In my draft, he returns to his cabin, is embraced by Shaw, who is delighted to see him having feared that he had died, and the two of them make love," he goes on to say. "And it's while they're making love that he bursts and dies. So that lovemaking sequence echoed my original lovemaking sequence where he explodes! It was messy."
"David, fascinated by these creatures, begins delaying the mission and going off the reservation on his own, essentially because he thinks he really belongs with the Engineers," Spaihts explains.
"They're smart enough and sophisticated enough, great enough, to be his peers. He's harboring a deep-seated contempt for his human makers. So at one point Shaw goes to stop him and David ties her up and deliberately exposes her to a facehugger. He caresses an egg open and out comes a facehugger."
"David doesn't smell like a person - his breath isn't moist - so he can handle the thing like a kitten. It doesn't want him; it's not interested. But then he exposes it to her and it goes for her like a shot. He toys with her for a bit and then lets it take her. That, in my draft, was how Shaw was implanted with the parasite that she had to remove with the medpod sequence."
