It never was scary, it has always been very stupid. Just because they can do something with a computer that is different, that doesn't mean the should use it for any projects. It might be fun to learn and play with to the people using the software, but they need to learn that it is not at all entertaining when used in a movie.

Is it really relevant how original the effect is in this context?

I just saw it as adding suspicion to the mother so as to take attention away from Elias possibly seeing his dead bro.

You are sooo right!

On the other hand, people's heads
not
doing that is used way more often.
I still enjoy the effect.

I think this effect was also in The Exorcist 3

Also Maryanne from season 2 of True Blood did this effect in the woods.

1. Jacob's Ladder
2. House on Haunted Hill
3. ??
   This is not the same effect as seen in those two films. It looks digitally manipulated here, which doesn't create the same type of motion. JL and HOHH both used film manipulation techniques (shooting at a low framerate and then speeding up) resulting in a different feel to the effect.
   If you can name other movies where this effect was used in that fashion to the same end result as those two movies, I could agree. However, I just haven't seen it overused.

It never fails to creep the hell out of me. : /

Wrong.
It's been done endlessly. And not just in films, but every derivative music video since Jacob's Ladder came out. Over, and over, and over again.

So two movies is "done to death"? Interesting

The House on Haunted Hill remake comes immediately to mind.

I like that effect and find it scary. Can someone recommend some more horror movies with this effect? I've only seen it in Jacob's Ladder so far.

Actually I was not watching this part of the movie properly, as I had to study for exams and had just thought to take a glimpse of it
(although I did watch the rest of it properly).
Thanks for telling me that by the way
Clark: Jonathan Kent; isn't it a little past your bedtime?

Right after said "head twitching"
the scene cuts to both boys waking up, startled
But, even this scene - as with the whole movie - can be interpreted in more than one way, I guess, which makes it all the more interesting.
Fine, fine, I'll leave! But first I'm going to bother these peanuts! Hmm? Yes? Hmm? HMM?

I didn't realize it was a dream sequence and for me it was the only scene which kept certain suspicions of mine on the mother. Otherwise I kept thinking that the mother seemed totally normal
Clark: Jonathan Kent; isn't it a little past your bedtime?

I hate that effect about as much as the overusage of white eyed evil grinny people. It's not f.cking scary at all why do they use it so much UGH
"Ever danced with the devil in the pale moonlight?"

Eh, I know what you mean, but I think we can cut this movie some slack, after all they only used it in one single scene (
which happened to be a dream/hallucination)
that only served to show how insecure and afraid the boys were, because of
their mom's appearance (or rather, the fact that she was now a complete Jane Doe to them, notice that the blur only starts when we're about to see her face, but because the boys don't know who she is/what she looks like anymore, we get something blurry)
.
Wasn't meant to be scary in the least, although the lead up to it and everything, I really like that scene, music, and the way it was shot.
Could they have done something else? Yes, I'm sure, but this definitely worked.
Fine, fine, I'll leave! But first I'm going to bother these peanuts! Hmm? Yes? Hmm? HMM?

But then there's people like me, who actually think that was one of the best scenes of the film. Her walking in the forest by herself- just wandering. It was creepy. It was dream like. And it worked. Also, from a technical standpoint- i felt that scene in particular benefitted from the 35mm film quality. I really don't think it would have looked the same shot with a digital camera. The colors practically bled onto the screen. By the way, I saw it before I knew what was really going on - so it had a great mysteriousness to it.

NO- it certainly is NOT in the Exorcist, and yes it certainly WAS first used in Jacobs Ladder. Furthermore, film aficionados who follow these things have written much about how that effect was first created.I actually think there is a story about how it was an accident at first or an experiment regarding FPS..Frames per second.
Yes, I cringed when I saw it because it's been not only overused, I feel that scene is one of the major weaknesses of the movie. This is not a film about the supernatural in any way. Then eating the roach. .cutting open the stomach clearly was a dream/nightmare so I accepted that.
I'm running out of crazy twisted psych horror films. please send help!

See the movie.

If you're going to argue like a child, at least provide some proof to your claim.
We've met before, haven't we?

No there isn't.

Yes there is.