Sir Arthur Conan Doyle’s adventures of Mr. Sherlock Holmes undoubtedly changed the genre of mystery writing in general, but what often goes underappreciated is just how scary many of the classic tales were, too. Thanks to the eerie gaslight lamps, the clip-clopping of horses, and the very nature of Sherlock Holmes’ job taking on conflicts that the police can’t tackle, the original stories always tended toward the macabre. Doyle’s prose style (usually couched in the voice of Dr. Watson) also lends the original stories a bit of a tremor: If the reader is supposed to feel nervous, Watson’s heart is racing. And in the most unnerving Holmes stories, the setting usually shifts away from London and to the scarier outskirts of the countryside, where hollowing winds raged and greenish fogs were more likely to give you a chill.

If you’re looking for an oddly immersive Halloween reading experience, here are five Sherlock Holmes stories to prevent you from having a good night’s sleep.

5. “The Devil’s Foot”

Three people are found dead in a country house in Cornwell, but the messed up part is that their faces are stuck in such way that makes it look they were happy and laughing when they croaked. The solution to the mystery borders on science fiction, at least the chemical variety these early stories are known for. But that doesn’t make the images at the beginning of the mystery any less terrifying. Most adaptations of this story usually play up one particularly dramatic plot-point: when Sherlock Holmes must test a chemical compound on himself and risk going murderously insane in the process.

4. “The Adventure of the Copper Beeches”

When a young governess named Violet Hunter tells Holmes and Watson that her employer forced her to get a haircut and likes to watch her hang out in a certain blue dress, you know shit is already weird. And as Holmes and Watson head out to the countryside to investigate, things get creepier. The spooks include a vicious mastiff, a secret room containing more cut-off hair, and a terrifying villain named Jephro Rucastle. On their train ride out to investigate, Sherlock Holmes outlines that he thinks all the psychos have moved out of the city, saying: “It is my belief, Watson, founded upon my experience, that the lowest and vilest alleys in London do not present a more dreadful record of sin than does the smiling and beautiful countryside.”

3. “The Adventure of the Engineer’s Thumb”

In a unique story in which Sherlock Holmes barely appears, Dr. Watson receives a patient who has just had his thumb totally hacked off. A poor struggling hydraulic engineer by the name of Victor Hatherley agrees to consult of fixing a hydraulic press, which is located you guessed it — a little bit outside of London. Seriously, the carriage ride Hartherly endures in this story is subtly creepy enough to make you wish none of these characters ever left the cozy rooms of 221B Baker Street. But when you throw in a few guys who are trying to make counterfeit money, shit gets really crazy. This doesn’t spoil anything, but there is an ax involved in this one.

2. “The Adventure of the Speckled Band”

“Speckled Band” is a favorite among Holmes fans for a reason: It starts creepy and gets even creepier. At the start, we learn a woman’s twin sister’s dying words were a bizarre accusation: “It was the speckled band!” From there we are drawn into one of the darkest Holmes tales of them all. Revealing what is meant by the “speckled band” definitely gives away the solution to the mystery, so if you want to know what the dying words meant, read the story. But know this: A bell which “appears” not to work is actually calling to “something” in secret at night, and the tale ends with Holmes “thrashing” at something in the darkness.

1. The Hound of the Baskervilles

Originally written by Arthur Conan Doyle as what he called a “real creeper,” the earliest drafts of this story wouldn’t have even included Sherlock Holmes. And yet, this novella, eventually published in 1904, was a “flashback” Holmes tale, appearing in installments in The Strand Magazine eight whole years after Doyle had killed off his famous hero in “The Final Problem.” Baskervilles is a weird story in the totality of the Holmes cannon, but as far as following the formula of the scariest Sherlock tales, all of the best and most effective devices are employed, but this time, Doyle turns up the creepy factor to 11.

The story is set upon the moors of Dartmoor in and around Baskerville Castle. There’s a dark, murder-filled family legend, the ghost of a phantom hound, and Watson being forced to spend the night with a shitload of unsavory people, all moving around suspiciously in the dark. It’s not the best or most satisfying Sherlock Holmes adventure per se, but it is one of the best horror stories ever written. There’s a reason why literary critic Michale Didra said that he had put off reading The Hound of the Baskervilles until he had “the right conditions” which required “a dark and stormy night.” And if you’ve never read it, maybe tonight, the horrifying magic of The Hound of the Baskervilles can happen to you.

Photos via Sidney Paget, BBC America

Ryan Britt is a staff writer for Inverse. He is the author of the essay collection Luke Skywalker Can't Read and Other Geeky Truths (Plume/Penguin Random House 2015). His writing has also appeared in the New York Times, VICE, The Morning News, The Awl, Clarkesworld, BN Sci-Fi/Fantasy, Tor.com, and elsewhere. He lives in New York City.