Dean Stockwell, who died Sunday at 85, made every movie and television show he was in better. As an actor, he had a scurrilous twinkle that could light up a scene. He started off as a child star in films like “Gentleman’s Agreement” and “The Boy with Green Hair” — the latter of which I was shocked to discover really was about a boy with green hair (I’ve never forgotten what a poignant urchin the actor made him).

Stockwell was born in Hollywood in 1936, the same year as Dennis Hopper, and if his career had taken a slightly different turn he would have been part of the James Dean/Marlon Brando new-wave-of-Method-Hollywood rat pack. (In his beautiful youth, with dark eyebrows and ripe lips, he resembled a more winsome Montgomery Clift.) In 1959, he took on his edgiest studio-system role, playing one of the kinky killers in “Compulsion,” the drama based on the Leopold and Loeb murder case, and he wound up sharing the award for best actor at the Cannes Film Festival.

Soon after that, though, Stockwell drifted into television (“The Defenders,” “Wagon Train,” “Alfred Hitchcock Presents,” “The Twilight Zone,” “Dr. Kildare,” “Combat!”), when it was all a lot less adventurous than it is today, and for a long time he more or less stayed there. He would occasionally pop up in a counterculture curio like “Psych-Out” or “The Last Movie” or “The Loners” (in which he played a Native American). But one of the most telling aspects of his career is that even as he personally embraced the drop-out hippie lifestyle, he wound up sitting out the New Hollywood almost entirely. He would do a handful of stand-alone TV episodes per year, and that was it — until the director Wim Wenders cast him in “Paris, Texas” (1984), and suddenly, as he was slipping into the heart of middle age, Stockwell acquired something else. Call it mystique.

An entire generation now knows Dean Stockwell from “Quantum Leap,” the playful and popular NBC sci-fi series in which Stockwell grounded the gimcrackery with his costarring role as an acerbic cigar-chomping womanizer. For some of us, though, his defining role will always be the one that immortalized him in film history. And that was his performance in David Lynch’s “Blue Velvet.” He’s at the center of what was — and I would argue still is — the most indelibly weird scene in any movie since the dawn of movies. It’s also one of the greatest scenes.

It’s important to recall the place that “Blue Velvet,” in 1986, carved out for itself. Lynch, coming off “The Elephant Man,” had already done his oversize mainstream movie — the 1984 version of “Dune,” which went down as one of the grand disasters of its era, though some viewers, in light of the new “Dune,” are now looking back at it fondly. (Personally, I’ve never had the courage to return to it.) Following the colossal failure of “Dune,” Lynch went back to doing what he did best: creating art out of shock and passion and surrealism and danger. “Blue Velvet” was a film noir that wore its insides on the outside, and Stockwell became its nightmare mascot, its grinning demon-creep, its iconic image of sheer out-there-ness.

He plays Ben, the leader of a group of drug-addled criminals who hang out in some sort of scuzzy half-lit roadhouse that looks like a Diane Arbus living room. Ben talks in a soft fey cuddle of a voice, the sound of which is oddly sincere but also quite funny when he follows Frank Booth’s toast to himself (“Here’s to your fuck, Frank”). He wears enough rouge and mascara to look like the emcee at an after-hours drag club in Vegas. But since Hopper’s fearsome Frank actually reports to him, that lets us know what a powerful figure Ben is in the local scuzz underground. His weirdness grows out of his power; Ben is a dude who can do whatever he wants. And Frank, on this night, wants him to do “Candy Colored Clown.”

So Ben, who looks like a candy-colored clown, stands up in front of the room in his huge-collared frilly open shirt and smoking jacket, brandishing a cigarette holder, using an industrial work light as his pretend microphone (it lights up his face), and proceeds to do an act of lip-syncing that is so hypnotic you’re tempted to call it bad-dream karaoke. He’s not actually singing. The sound is all Roy Orbison warbling “In Dreams” (“A candy-colored clown they call the sandman/Tiptoes to my room every night…”). But as the great Roy sings, and as Ben, standing in his self-styled industrial spotlight, mimics that song, you’d swear that you could almost hear him, and time seems to stop. The movie seems to stop. We’re no longer just watching “Blue Velvet.” The film has sliced through all our rational defense mechanisms, pulling us in like the TV set in “Poltergeist.”

Why is Ben standing there, miming that song? Because he wants to; because Frank, whose response to the song is so intense it looks like he’s going to either cry or explode (or both), wants him to. But really, Ben is doing this because David Lynch simply had to stage that scene, because it poured out of him, because he needed to see it and needed us to see it, and knew that Dean Stockwell, performing it with a private smirk that comes off as bizarrely innocent, even as it marks him as a figure out of a horror movie designed to scare children to death, would be the only actor who could make that scene cut across time itself.

Stockwell’s career got a jolt out of “Blue Velvet.” Two years later, he received an Oscar nomination for his delectable performance as a thick but street-smart gangster in Jonathan Demme’s “Married to the Mob” (his best scene: a slow-motion parking-lot shootout), and the week of that Oscar ceremony marked the series premiere of “Quantum Leap.” So Stockwell, at 53, was off and running. But he would never top “Blue Velvet,” and couldn’t, really, because in that movie he became an actor for the ages, an actor out of dreams. Where he will always walk with you.