- Tony's capture, imprisonment, and hazy surgery. Being held hostage in a part of the world where a lot of people will hate your guts, no one knows where you are, and these people are more than ready to execute you slowly. The scene of the terrorists filming their demands is quite chilling.
- Made worse in that when he's being dunked under water, the car-battery that's keeping him alive is shown sparking and nearly shorting out, meaning that Tony's not only being nearly drowned, but suffering mild electrocution and cardiac arrest at the same time!
- Horrifyingly, Tony wakes up while the electromagnet to keep the shrapnel out of his heart is being grafted to him. He can only scream in agonizing pain before being put under hurried anesthesia.
- The Ten Rings' invasion of Gulmira, made all the more chilling by the fact that, while the Rings themselves are fictional, their actions aren't. Massacres like Gulmira happen in regions all over the world where extremism runs rampant.
- After Tony's attack on the Ten Rings' weapons depot, he gets engaged by a pair of USAF Raptors, and after an accidental collision, one of the pilots is forced to punch out — but his parachute doesn't deploy. If Tony hadn't gone after him, that pilot would have been conscious all the way down — and his wingman and the guys in the command center would have had to watch.
- Stane paralyzing Tony and pulling out his arc reactor, all the while never dropping his Affably Evil personality and casually telling him that he's going to murder Pepper before leaving Tony to die a slow and painful death of shrapnel in the heart.
- A minor subpoint, but while Stane is talking, you might notice that Tony is bleeding from one ear thanks to the gizmo that paralyzed him. Maybe that's why it was never approved by the government...
- Even paralyzed, Tony can emote amazingly well despite his eyes being the only thing he could move voluntarily. When Stane tells him that he's coming after Pepper, Tony's eyes widen and the horror shines through as clearly as possible in that split second.
- The terrorist leader being left to the mercy of those he had been kidnapping and murdering.
- For some, this may fall into Nothing Is Scarier.
- Stane gives quite a lot of this. He's always Affably Evil, he often seems like he's acting in Tony's best interests, and yet he's an Omnicidal Maniac by the end of the movie.
- The scene where Pepper and Coulson come to arrest Stane at Stark Industries, especially when Pepper is alone. She walks over to some chains, and we know Stane finished his Iron Monger suit not long ago. But we've never seen the full armor. And then the arc reactor lights up, and the POV camera moves up, and Pepper begins to run. Cut to her and the agents pulling a Screw This I'm Out Of Here, while something huge tears apart the lab behind them and chases them. It's chilling.
Nightmare Fuel / Iron Man