- The effect that the alien fluid has on Wikus. Most of the scares in this movie run on the Body Horror of Wikus transforming into a prawn. First, there's the vomiting, which is gross, but not necessarily horrifying. But then he starts hacking up black liquid, which sends him to the hospital and then discovers his hand is turning into a prawn claw. And as the movie progresses, it gets worse, and then at the end, as Tania is being interviewed she shows the metal flower that was left at her door and then there's a cut to Wikus fully transformed into a prawn, making the flower in District 9. The fact that he still can remember his wife, and not knowing whether or not Christopher will return to reverse the transformation or if it can even be reversed is unsettling.
- The scene at the party in which Wikus vomits black liquid onto the cake, and then reaches in his delirium for the paper towels to start futilely mopping it up. That small, subtle gesture represented a last desperate gasp at clinging to normalcy, an attempt to put off just a little longer the horrible Body Horror that will characterize and shape the rest of the film. The way time stops and slows to draw attention to the precise last moment before reality irrevocably breaks is simultaneously terrifying and heart wrenching.
- Wikus's growing exoskeleton puncturing his flesh from the inside, causing it to bleed, and causing excruciating pain for Wikus.
- The scene where Wikus's fingernails start falling off, a Shout-Out to The Fly (1986).
- After Wikus's arm is first discovered in the hospital and he's forced into what is basically a body bag for transportation to MNU while still alive and fully conscious is pretty damn terrifying in its own right
- The MNU doctors attempting to dissect Wikus, live and fully conscious. Not that they managed to do it in the end, but the fact he was one of them, he worked there and they were willing to do it so unquestioningly. Plus his father-in-law just ignoring him.
- The scenes where Wikus is basically being tortured in the MNU hospital room.
- The MNU getting Wikus to test out the guns when they walk out a live prawn in front of him. What is even more awful is the fact that they keep on electrocuting him even after he agrees to cooperate.
- The scene where Wikus is scarfing catfood (which is pretty disturbing in itself), chokes and suddenly spits out a few molars.
- When Wikus tries to cut his alien claw-hand off, but instead just cuts off one of the alien digits. The pain is so great, Wikus then starts to drop the Cluster Fok Bomb.
- Wikus cheerfully taking a flamethrower to a nest of prawn eggs. The prawn babies are still alive. And they're screaming in pain as they're burnt. And if that weren't enough, Wikus cheerfully explains to the camera what they're doing, and then compares the popping sound it's making to popcorn.
- While out evicting aliens, Wikus is trying to lure out Christopher's child to be taken away, saying to his son "It's the Sweety-Man..."
- The Nigerians eating the poor alien.
- It's implied that the Prawns are not an invasion force, but just look at the weaponry they have on board. Taking it further, it's explicitly designed to only work for a Prawn operator, which could imply that there are other species out there the Prawns have clashed with in the past. Just what the hell have they been fighting?
Nightmare Fuel / District 9
Aliens being mistreated? Someone being infected and turned into one of them? Who would think there could be any Nightmare Fuel in that? Major spoilers below. Do not enter the District if you do not want to see them.