'The Metamorphosis' by Franz Kafka

"I read 'Metamorphosis' to see if it was really as cursed as everyone says it is."

"Yeah, I underestimated it. It was even worse."

- EviIIord

'The Jungle' by Upton Sinclair

"'The Jungle' by Upton Sinclair actually made me puke."

- Electrical-Cat6346

'Cows' by Matthew Stokoe

"'Cows' by Matthew Stokoe."

"I read it in eighth grade and I regret reading it, it was so gross."

- Rich-Brush9100

'Unwind' by Neal Shusterman

"'Unwind' by Neal Shusterman. There’s a scene in the book of it (unwinding) happening and I literally couldn’t sleep for a week."

"It really stayed with me and it took that same week for me to pick the book back up and finish it. So f**ked up and I felt that kids fear every step of the way."

- CuriousTsukihime

'Outer Dark' by Cormac McCarthy

"Probably 'Outer Dark' by Cormac McCarthy. I read it years ago, and it still lives in my head."

- Pirate_Queen_of_DC

'Wild Highway' by Bill Drummond and Mark Manning

"The most depraved book I've ever read is 'Wild Highway' by Bill Drummond and Mark Manning."

"Former KLF art terrorists on a quest to find Mobutu in former Zaire. Deeply racist, homophobic, misogynist, and violent. But can just about be read as the darkest possible satire, which I think it is. Probably."

"The only book where I actually, genuinely couldn't believe that what I was reading had been published. Just completely insane."

- RevPercySpring

'House of Leaves' and 'The Hot Zone'

"House of Leaves... not really f**ked up, just a weird a** read. Words can't really describe it. It's hard to read as well. Took about 100 pages before it got to the point where I didn't want to put it down."

"'The Hot Zone' and 'Demons in the Freezer' also. Kind of non-fiction written in a very story-driven manner. Both are scary beyond anything because one deals with filovirus like Ebola, and the other talks about smallpox."

"The one on smallpox states that each of the three level-4 labs in the world had a supply of smallpox. When the USSR fell, so did their Level-4 lab. Guess what? Their supply of smallpox is in the wind, no one knows where it went, so 1/3 of the world's supply may very well be in the hands of terrorists."

"My wife read 'The Hot Zone' when she was five months pregnant, and she couldn't make it past the first 40 pages."

- Sedawson74

'The Good Old Days' by Ernst Klee et al.

"'The Good Old Days' by Ernst Klee, Willi Dressen and Volker Reiss. It's an exhaustive compilation of all the documents kept by the Nazis of the Holocaust, as they were committing it (they were fastidious record-keepers and still had tons left over despite trying to destroy evidence in the final days)."

"Most people don't know this, and I didn't before I read this book, that the killing of Jewish people started when Polish citizens started dragging their Jewish neighbors to the local gas station or other public square-type areas, to beat them to death with lead pipes as their other neighbors cheered them on."

"Germany started institutionalizing this murder by then taking trucks loaded with hundreds of people at a time (this is after sequestering all the Jewish people into ghettos where they were told they were being held for 'processing'), taking them out to the woods, and shooting them all to death 10 at a time. They'd kill men one day, women another day, kids the next, and each day they'd do as many as 10,000 people."

"Then, when the Nazis found that their soldiers were suffering PTSD from literally killing truckloads of kids with machine guns every day, they started rerouting the exhaust systems on transport vans so prisoners would be asphyxiated in the back of them."

"And then, of course, the SS soldiers in charge were complaining about the disturbing noises they were hearing as people begged for their lives in death, as well as the horrific mess of tortured bodies they came upon when opening up the back of these vans."

"And then Siemens Corporation, a major German corporation which all of you will recognize is still in business today, discovered that a pesticide they developed, Zyklon B, was the most effective tool for asphyxiation. And this was YEARS after the Holocaust started. Millions were already dead, but many millions more would die to Zyklon B in just the last few years of the war."

"So yeah, I bring this book up whenever some absolute ignorant jacka** tries to claim 'it wasn't as bad as they claimed it was' or that 'it didn't happen.' My grandfather liberated one of those camps and has the photos to prove it."

"Most disturbing book I've ever read and I don't even think I made it all the way to the end."

- Ok_Marzipan5759

'1984' by George Orwell

"I read '1984' when I was 14 or 15 years old, and it kind of really hit me. Took me a few weeks to process properly."

- namedafteramovie

'Pinocchio' by Carlo Collodi

"The original 'Pinocchio,' which my mom thought would be fun to read to me when I was maybe four or five years old."

"Holy s**t. That book is so dark, so bleak, and so gory. Pinocchio himself is the most disturbing character in the story. He's not the lovable, if wayward, kid we see in the Disney movie."

"Book Pinocchio is a twisted little psycho who delights in tormenting people. Disney's Pinocchio learns valuable lessons from Jiminy Cricket. When the talking cricket tries to give advice to Book Pinocchio, Book Pinocchio smashes him to death with a wooden mallet."

"I saw that Disney made a new version and something inside of me just went, 'NOPE!'"

- shoesfromparis135

'Tender is the Flesh' by Agustina Bazterrica

"I'm about 2/3 of the way through 'Tender is the Flesh' now. I took a break from it because it's so rough."

"The human cattle aspect is bad enough, but the emotional hell the main character goes through is probably one of the more difficult-to-handle things I've ever read."

"It's so well written and definitely worth the read if you like books that ruin your day."

- fancytrashpanda

'All Quiet on the Western Front' by Erich Maria Remarque

"'All Quiet on the Western Front.' I read this book on my lunch breaks at the first job I worked at."

"I was not expecting the ending and literally sat there silent for about 20 minutes trying to process it before having to punch back in for work."

"Great book, highly recommend not reading it at work."

- rogue_giant

'Childmare' by Nick Sharman

"'Childmare' by Nick Sharman. My mum's boyfriend lived in a house share and one of the guys there left it lying about. 10-year-old me just started leafing through."

"The plot is that lead poisoning in the water supply drives the children of London insane. Insane like bullies beating weak kids' skulls with cricket bats, and stabbing another through the eye with a pen, and so forth."

"Read it as an adult and it's pulp horror crap, but at the time, it was pretty nuts."

- Regrettable_Tattoos

'A Child Called It' by Dave Pelzer

"'A Child Called It.' No question."

- fingerlessgloves47

Oh, the Middle School Curiosity

"'Flowers in the Attic' by V.C. Andrews."

"'The Lovely Bones' by Alice Sebold."

"'Lolita' by Vladimir Nabokov."

"All from curiosity when I was a middle schooler."

- pumpkin_breads

Each of these stories are spine-tingling and haunting by their own right, and perhaps it's best that this subReddit has now been "warned" before opening one of these books.

But there are bound to be some horror-lovers out there who will seek these out in pure curiosity now.