Most horrifying scenes (in non horror movies)?

[caj]

That transporter malfunction scene in Star Trek The Motion Picture scarred me for weeks after seeing it as a kid. I still won't watch it after all these years.

[K7P5V]

Hopefully this counts, but my next choice would be the Arkham flashback scene where The Joker recounts his torture of Tim Drake

[krazijoe]

The final scene in The Fly (1958). Yeah that scared the beejebus out of me.

[Scott Taylor]

Well that was suitably horrible

[Astroman]

I'd go back to the New Hollywood period:

The "Squeal like a pig" scene from Deliverance.
Pick a scene, almost any scene, from Midnight Express.
The broken legs scene from The Deer Hunter.

And from later on... scenes from the adaptations of Hubert Selby Jr.'s books Last Exit to Brooklyn (the climactic Tralala scene) or the ending scene in the adaptation of Requiem for a Dream.

That sort of thing is what I find to be where the true "non-horror" horror lies and why those movies have so much power.

[Username taken]

Hopefully this counts, but my next choice would be the Cobra Commander transformation scene in G.I. Joe: The Movie (1987):

Yes!

This is another one that "unsettled" me when I was younger.

[Gaius]

The Trinity test in Oppenheimer

[ChrisIII]

GHOSTBUSTERS has a few unsettling scenes I think (Don't think it counts as a horror film). While Vince Clortho's/Keymaster dog is played mostly for laughs, there's some unsettling moments with Zuul such as the first scene in Dana's fridge and later the bit with the chair.

The scene in the subway tunnel in Ghostbusters II is pretty much the most frightening-the "Winstonnnnnn!" voice, the ghost train, and then the heads on spikes (While might have seemed a nod to Vigo being partly based on the historical Dracula, but actually kind of added during production; not in the original script).

[Android 17]

Gotta add the scene in Batman Begins when Crane gets hit with his own toxin. His nightmare vision of Batman was horrifying.

[Kirby101]

"Is it safe?"

[Godzilla2099]

I know this sounds odd, but that scene in Who Framed Roger Rabbit where Doom slowly dropped that toon in to the Dip got me upset when I was a kid. I remember always fast forwarding that part when I got it on VHS because I didn't want to watch it again.

[Android 17]

I know this sounds odd, but that scene in Who Framed Roger Rabbit where Doom slowly dropped that toon in to the Dip got me upset when I was a kid. I remember always fast forwarding that part when I got it on VHS because I didn't want to watch it again.

Same.

Judge Doom was a damn nightmare. Remember when he was revealed to be a toon? That scene was scary too.

[ChrisIII]

Also disturbing how he goes from a cold villain to more hyper than Roger.

[DrNewGod]

"Is it safe?"

Excellent choice.

I'd throw in Messala's richly deserved fate in Ben-Hur (1959).

[K7P5V]

Yes!

This is another one that "unsettled" me when I was younger.

I know, right?! It seems he made a somewhat full recovery in the near future, at the very least...