The banshee toward the end of Darby O’Gill… was terrifying to me as a kid, R99. (I saw it in the mid-80s, though.)
Hotline (TV, 1982) starring Lynda Carter was also terrifying. My mom wanted to watch it, and I watched it with her. Can’t believe she thought that was okay. The ending was way too intense for me. I must have been no older than 4.
The Watcher In the Woods had so many disturbing sequences and visuals. I still can’t believe my 3rd grade teacher (and apparently many other teachers all over the US, I’ve come to learn) thought it was a good idea to show this to my class one afternoon. I still love this movie, and several scenes still make me jump.
The Exorcist was the absolute mother of all terrifying movies. I was always interested in and absolutely horrified by stories of people who lose control of their bodies and minds, so I was naturally drawn to this one when I first heard of it in second grade (‘86-87?). I had seen parts of it during TV airings, but never anything too scary, so I didn’t know what I was in for when my friends and I rented it (from a video that would rent any R-rated films to any children, no questions asked!). I made it to the first really outlandish “possession” scene, with Linda Blair’s throat bulging like a frog’s, and I was filled with such terror that I hit my face behind my blanket and screamed for my friends to turn it off. This was in broad daylight, by the way, on a sunny afternoon. My 2 friends laughed at me, but obliged. It took me a few more years and several more attempts before I could get through the whole movie. I kept trying to watch it whenever it would air on cable, but it was always too intense. (I was raised Catholic, by the way.)
Other “loss of control” stories that terrified me in a similar way, though not to the same degree as The Exorcist, were Sybil (Sally Field, 1976); an episode of The Wizard where a feral girl, raised by wolves, is the main “guest star”; and an episode of Scooby-Doo called ‘Make A Beeline From The Feline’, where Daphne’s aunt turns into a Cat Creature at night and robs jewelry stores.
Aside from the above, many if not most of the titles mentioned already in this thread also scared me as a kid, or at least entertained me tremendously. Salem’s Lot has plenty of truly creepy scenes and jump scares that are effective to this day. Ugh, David Soul’s hammy acting, though…