Nightmare Fuel / The Hand That Rocks the Cradle

• Marlene's highly disturbing death.
• Mrs. Mott's miscarriage and the operation which result in her needing a hysterectomy, which is a mixture of this and Tear Jerker.
• Anytime Claire's asthma flares up, particularly after she discovers Marlene's body, which got so bad, especially since Mrs. Mott emptied her inhalers so she would suffocate without them, she had to be hospitalized and put on a respirator. More disturbing, the death trap was meant for her.
• Mrs. Mott aggressively threatening and intimidating Solomon after he accidentally witnesses her breastfeeding Joey. She gets up close to him and asks him "Did you like looking at me?" in a flirtatious and sultry way, which makes him uncomfortable, and he tries to look away without saying nothing. The second time she asks him, her tone of voice is more menacing, and Solomon, who is still uncomfortable, says nothing. And then after a few seconds comes a hard slap from her. Solomon just freezes while Mrs. Mott coldly glares at him before smugly uttering, "Don’t fuck with me, retard. My version of the story will be better than yours." Up until that point, most of the things Mrs. Mott had been doing were underhanded, but not outright evil. This was her FIRST truly malevolent moment of the film, bullying a harmless and innocent man who has nothing to do with her plans for revenge or has wronged her in any way—but she does it anyway, out of sheer viciousness and to drive home that she’s not someone to be fucked with. Also, the cruelty displayed by Rebecca DeMornay is enough to make even the most calm and collected people feel downright uncomfortable.
• Mrs. Mott sneaking back into the house to attack and kill both Claire and Michael, and to kidnap Emma and Joey to start a new family of her own with them. It shows just how far she’s gone off the deep end and how delusional she’s become as she believes herself to be the children’s mother as she walks up to a terrified Emma, (who witnessed her attack Claire and knock her unconscious) telling her in an overjoyed and childlike tone "It’s okay, Emma. Mommy’s here. I’m going to take you and Joe. We’re going to have a real family now. You’ll never have to see these people again." Then she asks her, "So tell your mommy... where’s Joe? Huh? Where is he?" very deluded and disturbing, and if that’s not enough, there's the part where she encounters Solomon (who has been keeping an eye on the Bartels, despite being fired) trying to get the children to safety. He rushes to grab Joey to protect him from her after she demands him to give him over to her. When he says no, her response is "You give me my baby or I'LL BASH YOUR SKULL IN!" That right there is the textbook definition of batshit crazy!
• Not to mention the way Mrs. Mott taunts and mocks Claire despite having her at her mercy when she’s having another asthma attack. "When your husband makes love to you, it’s MY face he sees. When your baby’s hungry, it’s MY breast that feeds him. Look at you! When push comes to shove, you can’t even breathe!" That will give every single mother the creeps, and the way that Rebecca DeMornay delivers it makes it even more disturbing. Fortunately for everybody, Claire was faking her asthma attack to get Mrs. Mott to let her guard down.
• Claire being molested by Dr. Mott. The fact he’s a doctor, someone you should be able to trust doing something so monstrous to you alone is enough to give people the quivers.