It's amazing what computer graphics and clever camera tricks can create on the big screen these days. Since the late 1990s, more fantasy films have been made into movies than at any other time. The demand was always there, we just didn't have the technology to pull it off. Even if we have the technical knowledge, however, there are still a few fantasy books out there that are just too twisted, either in subject matter or in terms of visual execution, to be made into movies. Some ambitious directors, producers, and screenwriters have made the attempt a few of these, but have fallen well short. As the tech advances, we may see a few of these stories on the big screen in due time. Spoiler alert, if you haven't read these books yet!

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The Neverending Story, by Michael Ende

Wait a minute, you're thinking, this was a movie! In fact, it was several movies, wasn't it? Well no, not really. If you have read the original book, then you know what ended up on the screen was nothing like the novel. The original movie encompassed barely half the book and makes so many dramatic changes it's not even recognizable. In fact, legend has it that author Michael Ende was originally part of the crew and walked off the set in anger when he understood what was going on. If you've read the whole book, this doesn't come as a surprise at all. The Childlike Empress is revealed to be the main antagonist, Bastian betrays Atreyu in the most horrific way and is very nearly prevented from going home at all when he loses his memory. His adventures are as chilling and terrifying as they are beautiful, and the themes are love, death, memory, and betrayal. This really isn't a story for kids.

The Silmarillion, by J.R.R. Tolkien

A few years ago, The Lord of the Rings would have been on this list. Thanks to some brilliant direction by Peter Jackson and a mix of CGI and old-fashioned camera tricks, this book was brought to the big screen. When it was announced that prequels were being made, many people in the know logically concluded that that meant The Silmarillion. So why was The Hobbit chosen instead?

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Tolkien was an amazing linguist and gifted anthropologist along with being an incredible writer, and the Silmarillion is deeply complex. It describes the forging of the Rings of Power and the One Ring and the legend of Bern and Luthien, a tale that is retold through Aragorn and Arwen, along with the story of Sauron and his origins. The Lord of the Rings had to be watered down quite a bit anyway to be more palatable to modern audiences. Movies still have to be economically viable, and literature intended for children is a much safer bet when it comes to adaptation. Even The Hobbit had some vocal critics, so imagine how tough it would be to adapt the much more complicated Silmarillion. An upcoming TV show will tackle part of the time period, known as the Second Age, which is ambitious, to say the least.

The Left Hand of Darkness, by Ursula LeGuin

It's hard to choose just one of LeGuin's books for this list, as they are some of the most daring science fiction novels ever produced. The subject matter here might make certain people extremely uncomfortable. It focuses on a race that is essentially always a neutral gender but changes sex depending on the circumstances, usually only during mating time. The inhabitants of the planet Gethen, otherwise known as Winter, do not have a fixed gender. They shift from male to female in order to procreate, and incest is common and acceptable. When the Gethenians first come into contact with human beings, they are disgusted by their fixed gender and refer to them as "perverts." Society's views on gender and sex are rapidly changing, however, so perhaps the time for this movie has finally come.

'Till We Have Faces, A Myth Retold, by C.S. Lewis

So many readers are lulled into a false sense of security when it comes to the word of Clive Staples Lewis, thanks to the first few books of the much-beloved Chronicles of Narnia series. The further you get, however, the more twisted and difficult his books become. Lewis knew this, which is why he never sold the film rights to the books. Producers Walden Media clearly bit off more than they could chew, with The Silver Chair still languishing in development purgatory. The last two books of the Chronicles of Narnia could be on this list, but adapting them is a walk in the park compared to 'Til We Have Faces.

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A modern retelling of the Psyche and Cupid myth, this twisted tale will make your hair stand on end. The name comes from the part of the myth in which Cupid does not allow Psyche to see his face. C.S. Lewis takes us into a visceral world of murder, human sacrifice, sex and a bloody battle for kingship that would make the Lannisters of Game of Thrones blush. The book is told in the first person, making the view even more realistic. In the end, we discover that we are all Ungit, the jealous god, and we can never know each other until we have faces. It's worth noting that this was the last novel he wrote and that his wife Joy Davidson helped him out.

Shardik, by Richard Adams

The author of Watership Down had a lot to say about animal rights. He didn't care if his stories made people uncomfortable, either. Anyone who saw the animated adaptation of The Plague Dogs has some idea of how little Adams cared about upsetting people. This is how humans treat animals. Deal with it. And you can see how this doesn't make the greatest marketing strategy. Shardik has that same unapologetic attitude. Set in the fictional Belkan Empire, the story revolves around a bear who may or may not have spiritual powers. The novel includes some brutal battle scenes and one of the central themes is slavery, not only of people but of animals. In fact, Adams takes this a step further to include how both animals and children are exploited for profit and political gain, a bold move that would make many people uncomfortable.

Dante's Inferno

The fascination with this book goes back almost a thousand years. It not only gave the world the gift of vernacular Italian but also made strides in the realm of basic human rights, as it was one of the first books to openly criticize the Catholic Church and a repressive government. You have to admire Dante's bravery, and he paid a high price to express his views on paper. Several attempts have been made to bring the Inferno to film, and with the exception of the Italian film made in 1911 they aren't true adaptations. The 2018 movie was based on a video game, which takes a lot of liberties with the story, and a 2004 adaptation was based on illustrations that were based on the book rather than the book itself. Updated special effects aren't a good thing in this case, as we really don't want to see some of the horrors that Dante described in Hell.

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Other high profile movies have explored the concepts that Dante invented, like Spawn and Constantine, but those miss Dante's real message, and that was a stinging indictment of spiritual belief and church power. Dante believed that it was your behavior, not your standing in the religious hierarchy, that decided whether you went to heaven or hell. That was a revolutionary idea at the time and he was driven from his home in Florence for this indiscretion.

JLA: Tower of Babel, by Mark Waid

Graphic novels are on the same level as their conventional counterparts these days when it comes to film adaptation, so why not include one? Ask a comic book fan about one of the best stories to ever come to life on the page and Tower of Babel comes up immediately. Ironically, it's the popularity of superheroes that makes this a long shot for the big screen, as it pits them against each other in a rather ugly way. The story revolves around the Justice League from DC Comics, a roster that includes names like Superman, Wonder Woman, Aquaman, and Batman. It's the paranoia and solitary attitude of Bruce Wayne that gives the villain Ra's al Ghul the information he needs to defeat the Justice League. Although he was an unwitting accomplice, it's Batman's arrogance that drove him to compile the detailed records of his allies' weaknesses in the first place. he even invented the Red Kryptonite that almost kills Superman. Movie-goers tend to prefer stories with a clear line between good and bad, which is why the very lucrative superhero movie franchise hasn't even touched this, but the recent rise of the anti-hero might signify a change in this trend.

Dragons of Winter Night, by Margaret Weis and Tracy Hickman

There are some DND based modules that would make excellent films. This isn't one of them. Like the Silmarillion, it's not so much a twisted plot or subject but an incredibly complex storyline that makes this unlikely to even see the silver screen. A series would be a better bet, so we don't have to cram the myriad of details into a single storyline.

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It involves several epic battles and a complicated storyline with several threads that would be next to impossible to cram into a single film. To pile even more on to that, this is the second book of the Chronicles Trilogy and the second Dragonlance novel. It includes everything you love about the Dungeons and Dragons universe and then some. Cities destroyed by dragons, magical weapons, orders of knights, mysterious wanderers, and an array of characters that would be nearly impossible to keep track of in a single film.

Boccaccio's Decameron

A unique book even by modern standards, Boccaccio took his mentor Dante's inspiration to the next level. To start with, it's a complex metadrama with several stories taking place within one big story which would be confusing to film in the first place. It starts with a group of friends trying to escape the scourge of the Black Plague seek refuge in a house in the country, so already we're off to a chilling start. They entertain each other with stories and are challenged to tell the most heinous, disgusting and funny stories that they can. Some are realistic to a point, as Bocaccio always wanted reality within reach, but others veer off into the realm of the fantastic since the whole point is escapism. It is the final story that is the most hair-raising and ironically, the most grounded in reality.

Jabberwocky, by Lewis Carroll

To be fair, Monty Python took a crack at this, but it was hardly a big-budget movie and it was still pretty weird and barely watchable. The basic premise was also included in the Tim Burton film a few years ago, which was essentially a mash-up of both Alice's Adventures in Wonderland and Through the Looking Glass. This is a book within a book, as Alice finds it during her adventures, and the only way she can read it is by holding it up to a mirror. Even then, the poetry that makes up the novel is complete nonsense. Readers, puzzle aficionados and even mathematicians are still trying to figure out exactly what the poem means, never mind trying to adapt a screenplay out of it.

NEXT: 10 Books That Are Still Better Than The Movie