2. Cinderella

4. Aladdin and the King of Thieves

5. Sleeping Beauty

6. Hercules

7. The Fox and the Hound

9. Pocahontas

11. Peter Pan

12. The Princess and the Frog

Everybody dies, basically.
When mermaids die, they turn to sea foam and cease to exist. In the original fairy tale, the prince falls in love with a different girl, breaking the Little Mermaid's heart. She's faced with a dilemma: If she slays the prince and lets his blood drip on her feet, she'll turn back into a mermaid. Ultimately, she can't bring herself to do the deed, and instead flings herself into the ocean, transforming into sea foam.
The original Cinderella fairy tale is completely disgusting. When neither of her stepsisters can fit into Cindy's slipper, one of them cuts off her toe and the other cuts off her heel to fool the prince. Later, Cinderella has her magic birds peck out her sisters' eyes as punishment for their deceit. Oh, and she also slams the lid of a chest on her stepmother's neck, breaking it and killing her. Damn, Cinderella, you bad.
Even though The Lion King is completely plagiarized from a Japanese cartoon, Disney claims it's based on Shakespeare's Hamlet — a play in which pretty much everybody dies. In the climax, Hamlet (the character Simba is based on) is stabbed to death with a poison blade. Hakuna matata!
The original Aladdin's source material is pretty tame, but the movie's second sequel has darker origins. In Ali Baba and the Forty Thieves, the character Cassim (Aladdin's father) is killed and dismembered and his body parts stacked around a treasure cave as a warning to travelers. Later, Cassim's body is stitched together by a tailor so his family will think he died of natural causes.
In Giambattista Basile's 1634 work, the prince is unable to wake Sleeping Beauty from her slumber, which is caused by a flax splinter in her finger. So what does the prince do instead? He rapes her and leaves. Sleeping Beauty, still totally unconscious, becomes pregnant and gives birth to twins. One of the twins sucks on her finger, drawing out the splinter and waking his mother. Sleeping Beauty is like, "WTF, whose kids are these?" The end.
The movie Hercules is based on Greek myths, which are pretty much uniformly messed up. First of all, Zeus tricks Hercules' mother into having sex with him. Then, as a child, Hercules kills his music tutor with a lyre. Later, he marries Megara, but goes insane and slaughters all of their children. He marries three more times after that and he has countless male lovers.
Oof, this one's heavy. Don't even read it. Just skip to number 8.
Anyway, in the original novel, Tod collapses from exhaustion during a hunt and dies. Copper's alcoholic owner decides to move into a retirement home, but shoots Copper with a shotgun before he leaves. Literally the worst ending imaginable.
Victor Hugo's original novel sees Quasimodo betraying Esmeralda after she refuses to love him, which leads to her being hanged in the square. He feels bad, though, and lies with her corpse until he dies of starvation. Their bodies are found 18 months later, and when an attempt is made to separate them, Quasimodo's bones turn to dust. The world is cruel and wicked, indeed.
Pocahontas was a real person, and her life was kind of sucky. She kinda hated John Smith, who pretty much lied about everything that happened between them. She was also kidnapped, held hostage for a year, renamed Rebecca, paraded around as a propaganda tool, and then died at age 21. And then her grave was destroyed. But isn't "Colors of the Wind" a great song?
Lewis Carroll wrote Alice in Wonderland as a scathing satire on new controversial mathematic concepts, like imaginary numbers (you know, those things we learned about in high school). Carroll was super conservative and old school, and thought you'd have to be on drugs to believe in such advanced concepts.
In J.M. Barrie's novel, Peter kills the Lost Boys when they get too old: "The boys on the island vary, of course, in numbers, according as they get killed and so on; and when they seem to be growing up, which is against the rules, Peter thins them out." Dude, Peter. That's rude.
In the earliest version of The Frog Prince fairy tale, the frog's curse is broken when the princess hurls him against a wall. In some versions, the frog's head is chopped off or his skin is burned. Why any of these acts would break a curse over a simple kiss is anyone's guess.