This movie thoroughly endorses the trope NothingIsScarier and is pretty much [[UrExample the first movie]] to exploit the horrors of space (not counting '50s {{B Movie}}s), 11 years before ''Film/{{Alien}}''.
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* HAL is generally creepy all throughout the film, but the sequence where he [[spoiler:murders Frank Poole by ramming him with a space pod, severing his oxygen tube]] is outright ''terrifying'', not least because [[NothingIsScarier it occurs both offscreen and in complete silence.]] Not to mention the extremely quick series of jump cuts into the lens of HAL's camera before Dave sees Frank go flying past the screen.
** Even moreso, Frank's side of the experience. He's doing a routine repair job, when suddenly he is thrown out into space, his air hose torn. He can hear the flow of air get slower...and slower...as it gets colder in his suit...and harder to breath...
*** It may be worse in the film. We get [[SarcasmMode the sheer joy]] of watching his vital sign monitors fade to {{flatline}}s.
** Related to this, some viewers noticed during HAL's game of chess with Poole, that HAL is cheating, announcing a wrong turn and even declaring victory when not in a position to do so. The computer they are trusting their lives on is able to lie! Possibly a foreshadowing that something's not right with HAL.
** Daisy, Daisy, give me your answer do...
* His nearly silent, ruthless murder of the three hibernating crewmembers also definitely counts. "'''LIFE FUNCTIONS TERMINATED'''" will haunt your dreams.
* The approach to the Monolith is one of the eeriest/creepiest scenes in film.
* The famous "Beyond the Infinite" sequence is more [[VisualEffectsOfAwesome awe-inspiring]] than scary, but when it's intercut with images of Dave [[GoMadFromTheRevelation FREAKING OUT]], it gets really creepy.
* Dave [[spoiler:''very'' slowly killing HAL by removing his memory]]. HAL's CreepyMonotone is enhanced when you realize that [[spoiler:''he'' is terrified and he can't even express it]].
** It's made a bit more unnerving when you realize that Dave isn't so much [[spoiler: killing HAL]] as he is [[spoiler: lobotomizing him]], and the fact that you can't quite tell if HAL is just trying to trick Dave by appealing to his more emotional side or if he's genuinely scared.
* [[spoiler: That damn Star Child at the end of the movie is pretty creepy, especially when he looks right at the audience.]] This troper was 13 the first time he saw it and didn't watch the movie again until college.
* The bit with the monkey crushing the tapir skeleton with a club. This is the discovery of tools. If the music doesn't make it clear, it's supposed to be a singular leap forward for life on this planet. But then we realize it's just a more efficient way to break stuff and kill other monkeys.
* The monolith scene with the [[HellIsThatNoise hellish]] [[DroneOfDread droning]] [[OminousLatinChanting choral]] [[http://www.youtube.com/watch?v=GgqI32JX_jY music]].
* [[http://www.youtube.com/watch?v=-iVYu5lyX5M Lux Aeterna]](2001:Space Odyssey). Funny nobody mentioned this one. It is even scarier in the movie, with Jupiter and black void on screen.
** [[http://www.youtube.com/watch?v=JPa4XAhSYhE Aventures for 3 voices and 7 instruments]]. The original piece may be NightmareRetardant, but Stanley Kubrick's "unauthorized remix" turns it into ''ultra super high octane nightmare fuel''. And it sounds like all he had to do was play it through a speaker inside a metal bucket.
** "Music/AlsoSprachZarathustra" itself; [[ScareChord that first trumpet blast]] can easily scar you for life if it catches you by surprise. Especially when walking through the halls at night when every dark doorway happens to looks like [[TheMonolith that goddamn monolith]].
** And then there's [[http://www.youtube.com/watch?v=hpJ6anurfuw this]]. Thanks a lot, Portsmouth Sinfonia.
** [[http://www.youtube.com/watch?v=GgqI32JX_jY And this]], the epitome of HellIsThatNoise.