It's 1977. My older brother and I are staying up late watching The Twilight Zone alone in the darkened living room. He's 12 years old and I'm 11. Everyone else is asleep and I feel pretty cool for being awake after midnight, watching and enjoying this "scary" grownup show. I don't recall for sure which episode it is, but I feel like it was The Hunt, the one where (SPOILER!) an old hillbilly and his dog die while hunting raccoons and the loyal dog prevents the old fella from wandering into Hell. It's not one I've ever found all that frightening, so my guard is down.
There's an act break and a commercial begins. My brother and I both assume this is a Clairol ad, or some other hair care product. We see the back view of a woman brushing her long dark hair, reciting the "roses are red, violets are blue" rhyme. And after putting a flower in her hair, the figure turns, revealing A FREAKING SKULL YELLING AT US!
Of course this wasn't a hair care ad at all, but a commercial for Suspiria, a movie I wouldn't actually see for decades—and when I did see it, didn't realize that it was related to this image stuck in my head since childhood. I was pretty happy to run across this on YouTube a few years ago.
Of course, I had to send the link along to my brother.