Perhaps some of the most visually shocking terror in video gaming comes from Parasite Eve.
- Eve trying to create human body parts. At first it just sounds like she's trying to build a normal body, but when Toshiaki finds her results, it ends up she had created giant, free standing organs and left them hanging around the lab. And then we get a gruesomely detailed description of her taking the form of his dead wife.
- Eve possessing Asakura. Orifice Invasion through the mouth with detailed descriptions of vomiting.
- Eve raping both Toshiaki and Mariko.
- Flashbacks detail Kiyomi gradually losing control of her own body to Eve, unable to understand what's happening. For example, when Kiyomi and Toshiaki have sex, Eve forces Kiyomi's consciousness to sleep so she can have Toshiaki all to herself.
- Anyone who combusted in the movie, especially the Nurse. Watching someone being set on fire isn't pleasant, especially for what seems to be the longest minute of your life.
- The enemy is actually a real-life networked intelligence that has been dormant inside our own cells for millenia adds a second, far more cerebral type of horror to a game that's already likely to keep you awake for days.
- The fact that a normal living thing could, at any time, spontaneously combust or undergo a horrific mutation simply by being in close proximity to Eve. It's really saying something that combustion is probably the least nasty way to go.
- The Ultimate Being. Good god.
- The cutscene at the opera where everyone spontaneously combusts. Not to mention that you may think it's just All Part of the Show, then the actors stumble and fall into the audience and you think "Oh. Oh. OH NO."
- The mutation sequences. Normal animals transform into ravenous beasts of war, usually by way of forcing their bodies out of their skin and splitting their skulls open. Not just from this game, but from all games. The dog from the first game and the young woman at the Akropolis Diner in the second game come to mind. In the first case, the poor thing's head graphically splits in three. The young woman's mutation starts off relatively tame, but then her eyes turn red, her hair falls off, and her mouth rips in two.
- The scene with Eve at Central Park. The effects may have aged, but seeing all those people graphically melt into orange goo, with their bones showing, is still scary to this day.
- The scene in the Rehearsal Room with Melissa. Especially since it's heavily implied that this is the exact moment that Eve took over Melissa totally and completely, killing her in the process.
- Fighter jets getting blasted by the giant orange mass. For that matter, Eve turning one of the pilots into goo.
- Basically anything involving Eve could be considered Nightmare Fuel, especially when it comes to all her powers and just how horribly wicked she truly is.
- When Aya finally kills Eve, she has this creepy expression for a split second before she dies. Eve looks up at her with this smug smile as if to say, "I'll be back, bitch." But it's actually because she's the only one that knows that the Ultimate Being has been born successfully.
- So you think you killed the Ultimate Being? Guess again! Now it's crawling after you and gaining speed while the music playing sounds like an extremely sinister version of Jaws that has its tempo increased more and more as you progress. Just the music alone is enough to cause some form of panic.
- The normal ending, where something triggers the mitochondria in all of Aya's friends and the entire surrounding audience to start having glowing eyes with the implication that things are about to go to hell and a half. It says a lot that the alternate ending for completing the Bonus Dungeon is considered the canonical ending.