Memetic Mutation: Several lines from the film— notably "Stop whining!" and "Who is your daddy and what does he do?" among others— found themselves on an Arnold Schwarzenegger soundboard used by various radio morning shows for (likely fake) prank calls in the late 90s and early aughts, contributing to their memetic status. "It's not a tumor!" is another one that gets quoted a lot.
Special mention goes to "Boys have a penis. Girls have a vagina." Which gradually became famous due to how hilariously controversial such a line would be considered today.
Then, of course theres Arnold screaming shut up. Whether it be in video or gif form, expect it to pop up when somebody gets annoyed.
Nightmare Fuel: The big fire and shootout climax is pretty damn intense.
Kimble's nightmare. He dreams that during the kids' nap-time and while he's grading papers beside the window on a rainy day, Cullen Crisp slides into view from just outside to ominous music and slowly pulls a gun on Kimble who can only scream in silence before Cullen fires and he wakes up.
What Do You Mean, It's Not for Kids?: Tough guy Arnold Schwarzenegger finds himself out of his depth when he has to deal with a class of adorable children: a heartwarming family comedy, right? Well, not really. Between the crackhouse shoot-out that introduces Kimble in all his badass glory, to an abusive father getting punched by the hero, to the blue-lipped junkie cold on the slab after being spiked by the villain, to Kimble dreaming of Crisp shooting him, to O'Hara being caught having noisy sex with her fiancé, to Crisp holding his own five year old son hostage, to Crisp getting shot three times in the chest, to Kimble bleeding out in the corner of a bathroom as Eleanor Crisp demands her grandson, the film is definitely not for children. When they reviewed the film on their show, Siskel & Ebert urged parents to take the PG-13 rating seriously.