Posted over at Bloody Disgusting, these stills come from a bonus scene which will be included in the Blu-ray release of Prometheus. Below is the official description on how they shot the scene:
“Scott filmed the sequence both with the actor in makeup and without, providing clean plates that would allow for the insertion of the digital character. The final cut featured mostly makeup effects, which Weta enhanced with digital wire removal, bullet hits, and one shot of the digital creature’s body blended to the actor.”

The scene apparently supposedly reveals the fate to that ginger, punk geologist that ended up getting a face full of mutant worms inside the chamber. Apparently, he mutates into some sort of "digital character with elongated limbs and an engorged, transluscent head". Freaky, but what else could you expect from the likes of Ridley Scott?