WARNING: Per wiki policy, Spoilers Off applies to Nightmare Fuel pages. All spoilers will be unmarked.
The image on the right depicts some ghostly, ethereal place in the midst of an abyss of total darkness.
- In the topmost room of Hollow Bastion, the Princesses of Hearts' lifeless bodies are put out on display in crystal containers in the wall like trophies. The game never fully addresses how or why they're in there, but it's implied that some of them have been kept this way for years. With Birth by Sleep later confirming that at least Aurora has been in there for a decade.
- After his friends vanish, Winnie the Pooh starts wondering how he can "say goodbye to Pooh" when he disappears too. It comes off as a metaphor for suicide, which is rather disturbing given the source.
- The minute Sora enters the Second District of Traverse Town, he watches as some guy fades away with a horrified grimace on his face after his heart is freed from his body. Said heart then immediately turns into a Soldier Heartless.
- The manga has another interpretation of this scene. A Soldier Heartless rips out the heart from a woman (who's implied to be a prostitute) while she's flirting with Sora. Then the Soldier crushes the heart within his claws.
- On the night Destiny Island is destroyed, Sora sneaks outside only to find a storm, invulnerable Heartless devouring the whole world and Riku being swallowed by darkness. Even after he obtains a Keyblade capable of destroying the Heartless and defeats the giant being of darkness that towers over his islands, he's blown away as the world gets destroyed.
- One part of the final fight with Ansem has players fighting in almost complete darkness.
- The final boss itself can be best described as some kind of organic ship, connected to Ansem by thick, fleshy cords that may or may not be its entrails. Despite Ansem controlling it, said ship also sports a Nightmare Face of its own.
- Pinocchio's world is represented as Monstro. The inside of the whale is basically a Womb Level, and everytime it's accessed, the Gummi Ship doesn't land. It gets eaten whole. When it happens, you first see the Space Whale "swimming" on its own, then it spots you and swims towards you, and finally opens its mouth. It gets worse when you see everything from behind the Gummi Ship, and therefore you get to see Monstro's mouth as it covers the entire screen. Combine that with the final Fade to Black and what you get... isn't a pretty image.
- Dying can be rather startling. When the HP bar reaches zero, several things happen in rapid succession — Sora groans, the camera zooms in and circles around him, the screen fades to white, and the Game Over screen appears. In future games, it's slowed down, which makes it come as less of a shock.
- In the Game Over screen itself, Sora is unconscious, floating limp in complete darkness, with his heart floating outside of him.
- Xemnas' Early-Bird Cameo in Final Mix/1.5 Remix as a Bonus Boss is even more ominous than his proper Boss Battle in the second game. Watch it here. The way he speaks, without voice and causing his words to flicker and distort; the way he phases through things and flickers, as though literally out-of-sync with reality; and the way the game refers to him merely as "The Unknown"/"He Who Does Not Exist", plus his incredibly eerie boss theme all combine to make it probably the most haunting moment in the entire game.
- When the shark from The Little Mermaid appears out of nowhere in the haunted ship in Atlantica, it can be quite startling.
- The second boss battle against Ursula is terrifying for those afraid of the sea. A giant Ursula, deep in the depths of a swirling ocean. The only way to win is to swim right up to her face and attack. And if that wasn't enough, one of her attacks is inhaling water and pulling you into her mouth.
- Sora commits suicide. He does it for the sake of his friends, and it was all that saved Hollow Bastion, but a young boy still picks up a sword and slams it through his chest, entirely on-screen. And unlike most other Keyblades, the one Sora uses actually ends in a point.
- The battle against Chernabog is equal parts Nightmare Fuel and Awesome Music. The guy, as the interstitials of Fantasia outright state, IS Satan — he's a giant black demon, whose face is bigger than Sora is tall, and he's known as one of the most terrifying beings in the Disney canon. His presence is basically the huge sign that says "You're in the heart of evil, and it's only going to get worse even from here."
- Bald Mountain being the place that houses the entrance to almost the Realm of Darkness itself should say quite a lot about how Chernabog's area earned the name "Evil Grounds".
- And the best part? There's no warning he's even in the game. If you're playing it for the first time you don't even suspect him showing up this late in the story if at all. But no, he shows up as pretty much the penultimate boss of the game.
- Chernabog's demise once you defeat him is frightening as well. He roars in pain, throws his arms up, and is suddenly struck by a huge, purple pillar of light that sounds like a very deep, inhuman drone. We just barely get to see his wings flapping helplessly... and then he's gone, Bald Mountain now being empty.
- End of the World is a terrifying locale. The music, reprised from the tutorial, makes it seem so serene but you know it's the place of nightmares, being the remnants of countless worlds being destroyed by the Heartless. In the Final Dimension, you see pieces of destroyed worlds raining down constantly. It's truly the heart of darkness.
- According to the shout-out page, parts of the level seem to be inspired by Nowhere. Get that into your head for a second.
- Even the Gummi ship routes leading up to End of the World are pretty scary. The music starts out optimistic, energetic and fun, though space gradually gets darker in coloration. Then you get on your way to Hollow Bastion. The music becomes pretty dark all of a sudden, and space becomes very dark. It looks like you're driving through a whirlpool to the deepest darkness. Hollow Bastion is on the very brink of said darkness. Then comes the final journey to End of the World. You're flying in an almost completely dark abyss to the source of all evil in the game, with only a wispy, bright (though definitely not encouraging) array of purple light.
- And let's not forget the fact that it looks EXACTLY like a black hole, which is very fitting considering it's nature.
- Once you disembark for the first time, you're in the tiny "Gate to the Dark" cave. The name is already spooky enough, but there's no music. No sound besides the spookiest wind. Then you leave and enter the world proper, and as the music starts, you've finally arrived to the endgame.
- The mysterious final station of the World Terminus, where you enter a pillar of fire to find a mysterious lab with an even more mysterious message:Ones born of the heart and darkness, devoid of hearts, ravage all worlds and bring desolation.
Seize all hearts and consummate the great heart. All hearts to be one, one heart to encompass all.
Realize the destiny: the realm of Kingdom Hearts. The great darkness sealed within the great heart.
Progeny of darkness, come back to the eternal darkness. For the heart of light shall unseal the path.
Seven hearts, one Keyhole, one key to the door. The door of darkness, tied by two keys.
The door of darkness to seal the light. None shall pass but shadows, returning to the darkness.
Ones born of the heart and darkness, hunger for every heart until the dark door opens.
- After defeating Chernabog, you must venture into the now abandoned Bald Mountain. Inside, you'll find murals on the walls showing the wreckage of several Disney worlds, largely just the destroyed Princess worlds. Among them you'll find the animate trees from Snow White, just another casualty of the darkness.
- The Neoshadows, who appear in the secret endings, also were added to appear in the final general combat area of the game before the final boss as special enemies. These guys are already scarier, bigger versions of the Shadows, and they definitely prove why they were added as basically the very last generic enemies of the game, as they're strong, vicious, and work as a unit. They really can make you dread what's to come in the series' future.
- Oh, and while on the subject of Riku, the way he becomes when Ansem, Seeker of Darkness, takes over his body and turns him dark has to be plenty chilling. Especially the way Riku talks while possessed: he speaks with the voices of both himself and Ansem. Riku's own voice is dull and flat, and all the inflection comes from his "passenger".
- If you finish the second Hollow Bastion visit before you finish the Monstro stage, you still tangle with "Riku", only this time, Sora makes it clear he knows it's not Riku who's kidnapping Pinocchio. Ansem instead entirely uses Riku's voice, and mockingly asks things like "Don't you wanna play with your best friend?" It's very unnerving.
- It gets even creepier when Ansem shows his true form and tries to attack Goofy, Donald, and Kairi. Riku momentarily fights his possession, and holds Ansem back, crying out "No, you won't use me for this!" He was aware that Ansem was trying to kill Kairi using his body, and so he was probably aware the whole time he was possessed, but unable to really stop Ansem or do anything about it. Poor, poor Riku.
- The intro to the game itself is a sign of what's to come. From the unreal music to the all-consuming darkness surrounding your stained-glass prison of a tutorial space. The silence and lack of a voice or many other sound effects in the first stages doesn't help either. This all culminates with a massive shadow monster that you're expected to defeat, alone.
- The Heartless's ability to appear anywhere and attack can be Paranoia Fuel. In a hotel room? Yep. In a local bazaar? Yep. In an African jungle? You betcha. Almost nowhere is safe for Sora (or the inhabitants of the worlds, who are much less defended).
- Just that fact that countless worlds have been consumed is chilling enough, and the only way to know that one had been consumed is when a star suddenly disappears from the night sky. Very few people would survive, but most people are not so lucky. At best, they would've died. At worst? Well...
- And the fact that, for a good portion of worlds, Maleficent ordered their destruction if it means finding out if there's a Princess of Heart in them. But some worlds were just destroyed For the Evulz if Agrabah and Atlantica have any indication. While we will never know the exact number of worlds lost to the Heartless, Maleficent would have the highest body count of all Disney Villains in this series.
- When you get to Wonderland, the only notable residents you find are Alice, the White Rabbit, the Cheshire Cat, the Queen of Hearts, and her card soldiers. Several other noteworthy characters are missing, most notably the Mad Hatter and March Hare. The Heartless already invaded Wonderland to begin with, and when you make it to the unbirthday party, sitting in some of the chairs will yield Heartless to fight. You don't think...?
- The Phantom. Everything about this thing is the stuff of nightmares, and not just because of its difficulty. It's a Grim Reaper-like Heartless that eerily flies about like a banshee, just hanging out near Big Ben. When you fight it, it casts Doom on your entire party which, unless countered with Stop, will take out your party members permanently (just for the entire fight, but still) All the while, it will continually hound Sora like a horror movie villain and slice at him with its powerful strikes. Its Final Mix look also gives it more of a white color scheme, making it resemble an angel of death. And while you fight it, the ever-dire Destiny's Force plays in the background, highlighting just how terrifying it is.