1. The Original Night Stalker Sacramento Police Department / en.wikipedia.org The Original Night Stalker murdered 10 people across southern California from the late '70s through the '80s. He often targeted couples, forcing the woman to tie up the man before shooting them. He was never caught. 2. The Max Headroom Signal Intrusion View this video on YouTube youtube.com Don't watch this video if you want to sleep tonight. On Nov. 22, 1987, someone dressed in a Max Headroom mask hijacked two broadcast television stations while moaning, laughing, and screaming. The hijacker was never caught, but Reddit user bpaog claimed he knew who was behind the signal intrusion. 3. Capgras Delusion Jen Grantham / Getty Images The Capgras delusion "is a disorder in which a person holds a delusion that a friend, spouse, parent, or other close family member (or pet) has been replaced by an identical-looking impostor." One case report even detailed a 74-year-old woman who believed her husband "had been replaced by another unrelated man." She wouldn't sleep with him and actually "asked her son for a gun." 4. The murder of the Dupont de Ligonnèses David Vincent / AP Images In 2011, Agnés Dupont de Ligonnès and her four children were found murdered. Though investigators believe the family was killed between April 3 and April 4, neighbors claimed to have seen Agnés days later. Agnés's husband, Xavier, is the main suspect, but he has not been caught. 5. Unit 731 Tsugufumi Matsumoto / AP Images Unit 731 was a "covert biological and chemical warfare research and development unit of the Imperial Japanese Army" and was infamous for performing experiments on humans. Vivisections were performed on human subjects without anesthesia and prisoners' limbs were dipped in water and frozen to test treatment for frostbite. 6. List of Unusual Deaths Maso Finiguerra / Florentine Picture Chronicle You're probably already worried about dying in a car crash or from a heart attack. Now you can also worry about dying by having a turtle dropped on your skull or getting hit in the face with an airborne fire hydrant. 7. The Cleveland Torso Murderer gargantuen / Creative Commons / Via Flickr: 46596241@N02 It's just like it sounds. In Cleveland in the 1930s, an unidentified killer murdered 12 men and women. Often, the cause of death was decapitation, followed by dismemberment. The Cleveland Torso Murderer was never caught. 8. Overtoun Bridge Allan Ogg / Creative Commons / Via en.wikipedia.org The Overtoun Bridge is located in West Dunbartonshire in Scotland. Many dogs have leapt off this bridge to their deaths, usually from the same side of the bridge. In 1994, a man threw his infant son over bridge, believing he was an incarnation of the devil. Don't cross this bridge. 9. Kelly-Hopkinsville Encounter Cosmin4000 / Getty Images In 1955, seven people at a rural farmhouse in Hopkinsville, Kentucky, claimed to have been harassed and terrorized by "creatures similar to gremlins." If aliens exist, they are scary assholes. 10. The Keddie Murders The Sacramento Bee / wordpress.com / Via commons.wikimedia.org In 1981, four people renting a cabin in the Sierra Nevada mountains were found bound, bludgeoned, and stabbed to death. A steak knife found in the cabin "had been used so forcefully that the blade had bent approximately 25 degrees." The murderer has not been caught. 11. Grey Goo Wildpixel / Getty Images The Grey Goo is a hypothetical situation that would spell the end of humanity as we know it. Self-replicating robots would build more and more of themselves, consuming all of Earth in the process. So, like, no one build a replicator and we can avoid this shit, OK? 12. List of People Who Disappeared Mysteriously Ryan Mcvay / Getty Images The sheer number of people who have never been heard from again is overwhelming. This list has enough creep factor to make you never want to leave your room again. 13. Rat Torture Vitalii Hulai / Getty Images Torture is awful in general, but it's even worse when it involves something that can chew on you. During the National Reorganization Process in Argentina, rats were allegedly inserted into the rectum or vagina using a tube. And during the Dutch Revolt, bowls of rats would be placed upside down on prisoners' bodies and heated, so the rats would chew through people's flesh in an attempt to escape the heat. 14. The Voynich Manuscript Creative Commons / en.wikipedia.org The Voynich Manuscript is written using an unknown system and has been carbon-dated to the early 15th century. Cryptographers have tried, but no one has been able to decode this mysterious manuscript. 15. Kaz II ABC / youtube.com The Kaz II is often referred to as "the ghost yacht." Its three-man crew disappeared, but the ship was found in working condition with its engine on and a laptop running. 16. Cicada 3301 Bejim / Getty Images Cicada 3301 is an organization that sets up very complicated puzzles in order to "recruit highly intelligent individuals." People have claimed to have "won" some of the three rounds of recruitment, but no one has come forth to give detailed information on what exactly this organization is doing. Do they have some sinister plot to create some super-intelligent army? Will they destroy us? Who knows. 17. List of Unexplained Sounds Studio Grand Ouest / Getty Images Now that they've figured out that Bloop and Julia are the sounds of icebergs, you can settle into the unknown of Upsweep and The Whistle. They have yet to be identified, because the ocean is a vast den of terrifying, unknown shit. 18. Post-mortem Photography Creative Commons / en.wikipedia.org This page will remind you that there was a time when we posed the dead as if they were living so we could remember them as they were. But instead, we got terrifying dead eyes staring back at us. Nightmares for days. 19. Phantom Time Hypothesis Wavebreakmedia Ltd / Getty Images The Phantom Time Hypothesis alleges that the period of time between 614 and 911 A.D. was added in retroactively, and that events that happened during this time occurred at different points in history, or didn't happen at all. It might just be an unfounded conspiracy theory, but also what if the past and time is all a lie?!