Movie scares are often most effective when you don't know they're coming. That's why some of the most traumatic big screen moments have appeared in non-horror movies.
The Pink Elephants in 'Dumbo' (1941)
“Dumbo” is emotionally traumatizing enough, considering that 70 percent of the movie involves a baby elephant sobbing his heart out because the circus locked away his mother (and the other 30 percent involving problematic crows).
Shutting Down HAL in '2001: A Space Odyssey' (1968)
The climax of “2001: A Space Odyssey” is real heart-stopping stuff. The lack of dialogue and the sheer weight of Dave Bowman's isolation really begin to sink in, as Dave slowly makes his way across the station and begins systematically dismantling the out-of-control HAL 9000. By the time HAL is reduced to a slurring, singing shell of its former self, you just want this mission to be over with.
The Boat Ride in 'Willy Wonka & the Chocolate Factory' (1971)
This movie really makes you question Willy Wonka's motives for inviting five children into his fabled chocolate factory. Is he trying to find an heir, or is he just looking for an excuse to physically and psychologically those kids for a few hours?
Everything in 'Watership Down' (1978)
It's pretty much impossible to narrow this film down to just one terrifying moment. Watching “Watership Down” is an emotional gauntlet, one that reminds you just how horrific and inhuman the world can be for innocent rabbit heroes. You'd be better off forcing kids to watch the ending of “Old Yeller” on a loop for two hours.
Opening the Ark in 'Raiders of the Lost Ark' (1981)
The first entry in the Indiana Jones franchise established many tropes, one of which being that villains have to die in such a way that simultaneously punishes them for their hubris and grosses out everyone in the audience. “Raiders of the Lost Ark” had no trouble there. We'd almost feel bad for poor Major Toht if he wasn't, you know, a Nazi and everything.
The Ceti Eel in 'Star Trek II: The Wrath of Khan' (1982)
“Star Trek II: The Wrath of Khan” pushed the franchise in a decidedly darker direction. Nowhere was that tonal shift more apparent than when poor Chekhov found himself at the mercy of Khan's pet slugs. Who doesn't love a good dose of body horror in their sci-fi adventures?
Large Marge in 'Pee Wee's Big Adventure' (1985)
Pee Wee is a whimsical guy -- basically a hyperactive child trapped in a man's body and plagued by poor fashion sense. You wouldn't expect a Pee Wee movie to contain the most terrifying sequence this side of “The Exorcist.” But that's exactly what happened when our hero made the ill-advised decision to hitchhike and learned more than he bargained for about the legend of Large Marge.
The Death of Judge Doom in 'Who Framed Roger Rabbit' (1989)
“Who Framed Roger Rabbit” occupies this weird middle ground between lighthearted kids movie and dark deconstruction of the animation world. Nowhere is that more apparent that the climax, where Christopher Lloyd's villain is revealed as a toon wearing human skin and then subjected to one of the more unsettling death scenes we've ever found in a PG movie.
D-Day in 'Saving Private Ryan' (1998)
The D-Day Invasion in 1944 is infamous for being one of the most horrific and costly battles in World War II, and “Saving Private Ryan” succeeded a bit too well in capturing the scope of that carnage. The first 20 minutes of the film are basically a non-stop sensory onslaught. You have to admire the skill that went in to realizing this ambitious sequence, but that doesn't make it any easier to watch.
The Diner Scene in 'Mulholland Drive' (2001)
You could almost make a case for “Mulholland Drive” actually being a horror movie, but it's a little too weird and spacey to be pinned down to any one genre. But this scene definitely qualifies as outright horror. After spending minutes listening to a character recount his nightmare in painstaking detail, it's definitely a shock to see that nightmare abruptly come to life behind Winkie's Diner.
The Coffin Scene in 'Kill Bill Vol. 2' (2004)
Even people who aren't normally claustrophobic were probably put off by this scene, as Uma Thurman's embattled heroine fights to escape being buried alive. The way the entire sequence is framed and lit only adds to its intensity. By the time the Bride escapes, she's more than earned her vengeance.
The Demon Batman in 'Batman Begins' (2005)
“Batman Begins” takes such an earnest and grounded approach to the franchise that it makes those rare moments of unreality stand out all the more. We certainly weren't expecting to catch a glimpse of Batman filtered through the lens of Scarecrow's fear gas. We certainly can't blame Dr. Crane for developing a strong case of Bat phobia.
The Incinerator Scene in 'Toy Story 3' (2010)
Pixar movies are pretty great at manipulating our emotions, but only one film had us honestly believing that the entire cast was about to be horrifically killed during the climax. Woody and friends were narrowly spared a fiery death, but the whole ordeal came way too close for comfort. We're afraid to see what “Toy Story 4” might have in store for these poor toys.