The Legend of Boggy Creek, scariest movie ever made.
Well, it was a little scary, especially to my wife.
We'd been married just a short while when we saw it, and it shook her a little, especially as I knew a man who worked part time in a gun shop in Texarkana. That shop was owned by the brother (?) of the man who made the movie, and my friend said that although the tracks in the bean field looked fake, he was pretty well satisfied that there was a Fouk, AR "monster", a Bigfoot. One man was hospitalized afer being attacked by it and it terrorized some girls alone in a trailer or home.
My wife waited until I was in the shower, then threw a pail of cold water over the curtain and screamed like a Bigfoot.

Grabbed me and started tickling me as I washed my hair. Tsk, tsk, such doings...
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When, "Jaws" was released, I'd read the book and was eager to see the movie. The wife insisted on leaving pretty early in the movie and I didn't get to see it until after our divorce some years later. It did have its scary moments. BTW, I'd read all of the shark books that the police chief in the film was looking at.
"The Ghost and the Darkness" has a scary scene or two with the lions. I can barely stand Michael Douglas, whose role was created for the movie (and him

), but Val Kilmer was pretty good as the real Lt. Col. J.H. Patterson, VC, who really killed the two man-eating lions that temporaily stopped construction of the Tsavo railway about 1900. I have the book, written at the encouragement of Theodore Roosevelt.
Does anyone know for what Patterson was awarded the Victoria Cross? That's Britain's highest decoration for gallantry in combat, not for his bravery in pursuing the lions. He eventually killed the two main malefactors, but even today, man-eating is more common around Tsavo than in other parts of Kenya.
Some military movies are scary. When Wm. Holden's character was shot down in, "The Bridges at Toko-ri", you knew that he probably wasn't going to be rescued, despite the helo landng. And, "We Were Soldiers" has probably scared some and made many cry for what happened to those men. Both of the real helicopter pilots portrayed finally received overdue Medals of Honor for extreme bravery in taking in ammo and water and extracting wounded in the face of enemy fire so withering that most pilots would have refused to fly into that cauldron of horror. At least one DSC was awarded to one of the men portrayed (Sgt. Savage), and maybe more. UPDATE, April 14, 2015: I have since found that the officer commanding, played by Mel Gibson, received a DSC. I think he fully deserved it, as did Sgt. Savage.
Some of the Bond movies have scary stunts, but the ones with gadgets scare me less than the original, "Dr. No", where Bond is lying in bed and realizes the tarantula is crawling on him. (In the book, it was a centipede, and Fleming wrote it well.)
Oh: have you seen, "The Collector", based on the novel by John Fowles? My date kept repeating, "You know, there are really people like that". The kidnapping by the nut case really shook her. I was young, and saw more good movies then than are now made.
"Zulu" has its moments. I liked the scene where Lt. Bromhead earned the VC by going onto the fragile thatched roof of the hospital building, using a fixed bayonet to drive off Zulus firing on and throwing spears at the wounded and sick in the building. I have a book that shows the real Bromhead, Lt. Chard, and the others portrayed in the movie. But relatives of Private Hook, VC, successfully sued the producers for making him look like a bum and general miscreant.
The scene where the Zulu show themselves on the ridge before they attack Rorke's Drift was pretty sobering. I wrote a college paper on the Zulu and read Donald R. Morris's book, "The Washing of the Spears", so knew what the British troops were facing. And they had just received word of the massacre of a far larger force by the Zulu at Isandlwana. It must have been a terrifying thing to see them approach in their thousands. BTW, the narration was by the late Richard Burton, maybe because the actor was Welsh, as were most of the heroes of Rorke's Drift. (Some were English; one Swiss. In the movie, one was Afrikaans/Boer, but I don't know if he played a real man.) Eleven Victoria Crosses were awarded to the real defenders, which should say something about the battle. I imagine that it was VERY scary!