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Nightmare Fuel: Fantasia
"Fantasia" is the most "adult" classic full length animated film Disney ever made. This makes it already a bit different than most of their other full length animated films. Almost all of the segments take place in the dark.
"Toccata and Fugue"
Near the end of the segment a strange shape can be seen walking from the camera back to the distance. It is shaped as a coffin and accompanied by very frightening music.
"The Nutcracker Suite"
The start of the segment has an eerie atmosphere to it. Tiny little lights floating in a pitch dark forest. The music doesn't help much either.
The Mood Whiplash of contrast between the quiet fish dance and the loud Russian flower dance, can be startling.
"The Sorcerer's Apprentice"
The wizard (YenSid) has a very eerie piercing stare in his big eyes. He never ever speaks, which makes him appear all the more menacing.
Interestingly the opening scene with him sets up this trope, then subverts it—Yen Sid seems to be summoning some sort of creepy, disturbing skull imagery...only for it to blend together and become a beautiful butterfly.
The idea of something as inanimate as a broom suddenly walking around ... and then taking a will of its own!
The way the chopped up broom slowly but surely comes back to life. Mickey then hearing sounds from behind the door and taking a peek...
Mickey almost drowning in the whirlpool.
Yen Sid providing a Jump Scare moment by suddenly hitting Mickey with the broomstick.
"The Rite of Spring".
The creation of the universe is very eerie, due to the threatening music. Especially when Earth comes closer and it seems as if the viewer will be crushed by the planet.
The never slowing down or stopping lava stream.
The scenes taking place in the deep ocean. The music itself is very spooky, especially during the first scene where organisms split up to form cells. What makes this scene particularly frightening is that most children have no idea what is going on!
The appearance of those Gallimimuses who head towards the river to drink. The music is eerie and they move like zombies, complete with glazy stare and jerky movements.
The brutal battle between the Stegosaurus and the T-rex.
Hell, the T. rex himself! If he doesn't scream Prehistoric Monster, then I don't know what does!
The dinosaurs dying from starvation is also very disturbing. Especially the one who wants to dig up something to eat and then slowly realizes there isn't anything there. While he sits there, tired of his fruitless search the desert wind starts blowing against his back and you realize he is doomed.
If that's not terrifying enough, there's the T. rex collapsing from the heat. Once it was a powerful creature feared by all, now even it is rendered powerless by nature's wrath and is forced to join in the march towards extinction.
Or what about the solar eclipse at the end of the segment? It's just so eerie that something so familiar as the sun can be so frightening.
The idea that this truly haunting event happens more often than once a year, near that quiet little city near the bald mountain... You just hope that the villagers don't realize what happens near their town each night!
Chernabog's eyes! And his powerful gigantic arms are also something you don't wish to encounter in real life.
Chernabog grabbing a handful of demons while he looks at them with an endeared smile. Then he just drops them into the lake of fire, as if he lost interest...
The harpy grabbing a demon but then (accidentally?) dropping him, causing him to plummit to his doom inside a seemingly bottomless pit of fire!