This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / RoboCop (1987)
Early in the film, before his resurrection as the title cyborg, Murphy is captured by Boddicker's gang, who proceed to graphically dismember him with shotguns, blowing his arm off and blasting endless rounds into his torso from a distance, before finally killing him with a close range shot through the head. Murphy is conscious and screaming horrifically throughout, up until the final headshot. Such is the sheer brutality of this scene that even in its edited-for-television version, it is still hard to watch.
The scene was even referenced in the cartoon series. Kids show or not, it's still a shock.
If you've ever been sedated for surgery, or experienced a near-death experience, you may be able to more easily imagine what Murphy goes through: You're brought into an emergency room, horrified that your family will lose their father. You see a film of an unseen vehicle taking you away from your family as they wave "good bye" fully expecting to experience death...
Then, all of a sudden, you experience a sort of static before some undetermined time later being powered up and off like a computer several times, with an unknown amount of time between those powerups and powerdowns and while on seeing and listening unknown scientists and executives messing and talking about nasty things to do on you, being unable to talk and much less move. At the end you're seeing the world through an interlaced camera feed, with your fundamental memories removed from you, and experience broken traces of your removed memories. Your family believes that you have died, and you are left wondering who you are.
Kinney's death when the ED-209 malfunctions. Yes, it's meant to be Bloody Hilarious, but come on, you'd be scared shitless too if you were in the same situation in that short moment before getting gunned down relentlessly by something you thought was safe.
During the final shootout between the titular cyborg and Clarence Boddicker's gang in an abandoned chemical plant, Emil is shot at by RoboCop and crashes the panel truck into a vat of toxic waste...and survives. The effect of the waste on him (as seen in the image above) is both nauseating and terrifying, he is visibly melting and dissolving, while alive, staggering around and moaning desperately for help. It is almost a relief when, later in the sequence, he is accidentally run over by Boddicker and promptly explodes from the impact, showering the windscreen in what appears to be brown water, rather than blood.
The stop-motion animation of the ED-209. The jerkiness accentuates its creepy robotic motion. The way it moves puts it right in the Uncanny Valley.
It even sounds creepy; at one point in the film, when it gets turned over on its back and can't turn itself the right-side up, it lets out these horrific pig-like squeals.
Boddicker getting stabbed in the throat by Robocop's bayonet jack and collapsing and screaming while his blood sprays all over the place. Robocop is practically covered in it by the time he collapses.
Emil's reaction to Robocop after finding out who he really is. While awesome in our POV as Robo finds out who he is and what Emil along with the rest of the gang did to him, in Emil's POV it's much more scary. Emil was just doing what was normally routine, a robbery, then he meets Robo which is bad enough, but then he hears the line "Dead or alive, you are coming with me." Cue an Oh Crap! from Emil as he is facing the man he and his friends killed. His first reaction is to shoot at him, but unlike before, the bullets simply bounce off. To Emil, it's a metallic vengeful ghost coming for him.
Murphy without his Robocop visor. His head essentially just a human face stretched over a metal skull.
The moment you realize he doesn't even has a head anymore; he is just a brain, some medula and a primitive digestive system. His heart, lungs, circulatory and respiratory systems are replaced with cybernetic implants; has no eyes, cannot taste, doesn't "breathe". The "face" they give him still has the bullet hole that killed him. When he tries to arrest Dick Jones, Directive Four kicks in and is shutting him down, wich would in effect either kill him or put him in a And I Must Scream state until reactivation, entombed within his robotic body with no sensory input he'd most likely than not go crazy within a few hours.