The crew is attacked by the temple's "guards" -- a host of SPACE TAPIRS
, vicious, bloodthirsty killing machines created by the Engineers to protect the ampules while the Engineers are in cryosleep. The space tapirs also spit acid, by the way--Fifield and Holloway get hit in the face with some.
The crew beats a desperate retreat back to the ship. Fifield starts going crazy, because it turns out the space tapir acid also, like, mutates you into a space tapir
. After a nasty rampage in the garage, the proto-tapir gets torched. Everyone conveniently forgets about Holloway. He sleeps with Shaw, and gets her pregnant with a Tapir baby, which rapidly matures. Weyland, realizing the power of the space tapirs, conspires to keep Shaw in cryo so he can extract the Tapir baby back on Earth and harness it for the bioweapons division. Shaw rebels and sneaks away to have the fetus removed. Horrified by her hideous offspring, she tries to attack it with an axe and kill it:
The space tapir, which rapidly grows to maturity, fights back, but doesn't harm her. Then Shaw gets attacked by Holloway, who is now part man, part Space Tapir. He is about to kill Shaw when her Space Tapir child bursts through the wall and DESTROYS HOLLOWAY! It then corners Shaw in the hallway:
Curiously, it does not kill her--instead, it sniffs her affectionately, recognizing that Shaw is its mother! A bond is instantly formed, as Shaw's maternal instincts kick in and she decides to protect her Space Tapir child at any cost. She confides in David, who being an outcast and an android, understands or something. The two form a plan to smuggle the Space Tapir off of Prometheus so it can return to the temple and escape being exploited by Weyland. David goes to open the hatch so that Shaw can escape with Space Tapir--only to find Vickers waiting for him:
The two have an altercation in the hall as Vickers attempts to stop David and Shaw from releasing the Space Tapir. Shaw tackles Vickers, and David and Space Tapir run out of the ship and back to the temple. Vickers throws Shaw in the brig and says she is going to find Space Tapir whatever it takes. Shaw breaks down and begs Vickers to reconsider, says the Space Tapir is her child and that she loves it and Vickers would understand if only she had children. Vickers says "okay" and decides to help Shaw.
Meanwhile, in the temple, David and Space Tapir discover the Derelict ship's pilot room. David activates the holo-chart orrery and marvels at it. Unfortunately, he wakes up an Engineer, who kills him and starts to activate the pilot chair. Space Tapir sees David's fallen body and grieves for his friend:
As the Engineer charts a course for Earth to reclaim it for his people, Space Tapir vows revenge--for killing David, for creating and enslaving the whole Space Tapir race, for everything
. Space Tapir drags David's body to ampule room, and using the BIOFORM contained in the ampules, he fuses himself with David, thus making him half android/half Space Tapir--the first biomechanoid is born
. Space Tapir then attacks and kills the Engineer, and then gets into the Jockey chair to try and stop the ship from taking off:
But it's too late, the ship is programmed in its course, and now Space Tapir is trapped in the chair! Space Tapir, who by this point has established a telepathic link with Shaw (ala ET), tells her of the danger to her planet, and tells her the ship must be destroyed and his life must be sacrificed to save humanity--he is, in fact, the metaphorical Prometheus of the title, stealing the Engineers technology and then dying in a fire to save humanity (Lindelof is apparently really proud of this plot point--who can blame him?). Shaw screams "NOOOOOOOO!!!" and then radios to Vickers what's going down, and Vickers convinces Janek to crash the ship into the Derelict. She escapes in a pod right before the impact. She meets up with Shaw on the ground and the two manage to outrun the falling Derelict. As it finally settles on the ground, Shaw tells Vickers they need to go inside and save her Space Tapir son. Just then Vickers rips off her face, revealing that she is another Space Tapir!