Deadman Wonderland/Nightmare Fuel

Just the whole concept of it. It's like Oz meets Elfen Lied meets more insanity.
Episode 1: within five minutes of the first episode you get to see a classroom of middle school kids mutilated into shredded corpses covered in glass, concrete, and their own dismembered bones and blood. And then you see Mimi's bloadsoaked head clutched in the Red Man's hand like a trophy... with the most horrified look on her face. What does that imply? She saw the whole thing and begged not to be killed. But the Red Man found it more pleasing to his sick gullet to just put her out of her misery.
- And then comes the trial. Not only is Ganta a helpless little kid under the mercy of an iron-fisted court, he has nobody with any moral fiber to defend him. On top of that, he's seamlessly impersonated and incriminated with evidence he's an insane killer. After panicking at the sight of everyone ready to convict him, he looks like he's lost his mind... which of course, causes the grief-stricken parents of the victims to think he has no remorse (for a crime that wasn't even his doing), and beat the hell out of him. Next, his corrupt bastard lawyer deserts him and he gets a life sentence. Then, of all things, he gets egged. Finally, he's placed in a jail that can only be described as Satan's playhouse. Think you're having a bad day?? Like hell you are compared to this shit.
The dog race from episode 2. The fact that the audience were watching real people die.
Shiro as a little girl having her arm break into pieces and trying to put it back together.
If you have a little sister, niece, daughter, etc. do not I repeat do NOT watch Shiro's backstory.
The stuff that happened to Shiro in her youth. She was infected with all manner of extremely dangerous, extremely potent diseases, viruses, and chemical weapons, repeatedly and without treatment. It left her in constant agony that she tried hide when she attempted to have some normal happy playtime with Ganta. That is, until her body literally started rotting apart, and she could feel every second of it. And It Got Worse. After her regenerative and blood controlling capabilities were revealed, she was vivisected repeatedly, without anesthesia and had large chunks drilled or gouged out of her body, again without anesthesia.
Are you a Knight in Shining Armor? Thinking of White Knighting? Do NOT ever, under any circumstances, try to help someone in Deadman Wonderland this way...you'll end up dead due to the seemingly Moe but really Ax Crazy Minatsuki.
Ganta being tortured by being forced to watch the Carnival of Corpses. He has a breakdown as a result.