I remember being scared by Regan and Judge Doom, yeah - but nothing scared me more, as a kid, than Leon's death in Robocop.
He's tricked by Murphy into driving into the most structurally unsafe vat of acid, puncturing and causing his car to be flooded in the stuff. What emerges from the torrent of hissing, yellowish, noxious stuff is deformed, fiaccid, gargling and obviously wracked with agonizing pain. Paul Verhoeven's camera lingers for an EXTREMELY long time on him, the music and actor suddenly dropping out of their prior "Nyeheh, I'm a mousey little spastic sociopath!" mood to full-on pathos. The score practically screams "STARE AT THIS WRETCHED BEING, CHILDREN! EMPATHIZE WITH THIS HUSK OF A MAN!" as he starts lurching forward.
Finding one of his fellow goons, he clings to him and gargles a plea for help, which goes ignored. A few moments later, Clarence Boddicker's car runs him over. Instead of merely disappearing under the car's wheels or being flung over it, Leon explodes like a water balloon filled with liquefied former viscera.
Consider that they sold RoboCop action figures, back then. Toys my childhood friends played with in impunity.
It's the vilest thing ever, and not even the most unhinged splatter flick out there manages to gross me out as this action movie did with that one scene. I kept having nightmares about Leon's mangled, half-melted form lurching into my bedroom, gargling for help...
Edit: I said I couldn't find it, but leave it to a Spanish uploader to find that very segment, or at least its most important part...
<youtube=gZabXFTOOrM>
I just - argh. I think I'll go take thirty-six consecutive showers in a tub of hand sanitizer, now.