Capgras delusion is a psychiatric disorder which will make you believe your friends, family or pets have been replaced by identical imposters.
2. In the 1970's, USSR built a system nicknamed Dead Hand. This system was built to work as a fail-safe in the event of a nuclear strike. It would then automatically launch multiple ICBM missiles to predetermined target without the need for input from a human. It is still running so a computer from the 70's is all that stands in the way of an all-out nuclear war.
3. A secret organization called Cicada 3301 has on six occasions posted puzzles and alternate reality games (some lasting years) in an attempt to recruit code breakers from the public. It has been called “the most elaborate and mysterious puzzle of the internet age.” People speculate the puzzle to be a recruiting tool for NSA, CIA or MI6. No one has taken credit for it nor has any individual who solved the puzzles has ever come forward.
4. In 1988, a 17-year-old Japanese high school student named Junko Furuta was abducted and tortured for 44 days after which she was murdered. The murder was perpetrated by four teenage boys. According to their trial statements, the four of them: raped her over 400 times, beat her several times, starved her, hanged her body from the ceiling and used her as a "punching bag", dropped barbells onto her stomach several times, forced her to eat live cockroaches and drink her own urine, forced her to masturbate in front of them, inserted foreign objects into her vagina and anus, shoved a still-lit light bulb into her vagina, set fireworks into her anus, vagina, mouth and ears, burnt her vagina and clitoris with cigarettes and lighters, burnt her eyelids with hot wax and lighters, tore off her left nipple with pliers and pierced her breasts with sewing needles. All four of them were arrested but were only given light sentences for their atrocious crimes because they were teenagers.
5. Convicted serial killer Albert Fish a.k.a. The Brooklyn Vampire was a child rapist and cannibal, who boasted that he "had children in every state." and at one time stated the number was about 100. He was put on trial for the kidnapping and murder of Grace Budd. He was captured when police investigated a letter that he had sent to the mother of Grace Budd, in which he described how he killed her 10-year-old daughter and ate her. When he was executed, he even helped the executioner position the electrodes on his body before uttering his final words, "I don't even know why I'm here," before he was killed by two jolts to kill him.
6San Fernando massacre
In 2011, Los Zetas drug cartel committed a massacre in San Fernando, Mexico. Cartel members hijacked a number of buses along the highway and kidnapped the passengers. Female victims were raped and able-bodied men were forced to fight to the death with other hostages. They were given knives, hammers, machetes, and clubs. Survivors were recruited as a hitman for Los Zetas. All in all 193 people were killed and buried in 47 clandestine mass graves.
7. Charles Domery was a Polish soldier of normal build who is noted for his unusually large appetite. He surrendered to the French for food, ate 174 cats in 1 year, often ate 4-5 pounds of grass a day, and after a fellow sailor’s leg was severed, he began to eat it. The prison gave him 10x the rations, but he still ate rats, cats and candles to quench his appetite.
8. There exists a secret group of investigators named Aerial Phenomena Enquiry Network who specialize in the field of UFOs who regularly contact researchers via letter and cassette tape offering pieces of information, yet never supply contact details. They were active from 1974 to 1990s. They have brought a number of UFO incidents to the notice of the general public when the information was only available to the government.
9. Alien hand syndrome is a rare neurological disorder, in which one hand functions involuntarily, often in direct conflict with the other hand, with the victim completely unaware of its actions. People affected by it can pick things up, throw them and even attempt to strangulate themselves, having to use the controllable hand to restrain the alien hand. There is no known cure for the alien hand syndrome.
10. Andrei Chikatilo was a Soviet serial killer who killed at least 52 women and children from 1978-1990. In the process of trying to catch him, Soviet police solved more than 1000 unrelated crimes, including 95 murders and 245 rapes. The first time he was captured he was released from custody because his semen type was different from his blood type, which is extremely rare. He even helped police with the investigation at that point. When he was executed, he exclaimed “Don’t blow my brains out! The Japanese want to buy them!”
Tarrare was a slender French man who lived in the 1700s. He had a bizarrely insatiable appetite which could never be satisfied. He would regularly eat a meal intended for 15 people in one sitting and under medical observation ate cats, snakes, lizards, puppies and an entire eel without chewing. He would scavenge for offal in gutters, rubbish heaps and outside butchers' shops, and attempted to drink the blood of other patients in the hospital and to eat the corpses in the hospital morgue. He was even suspected of eating a toddler.
12. Teratoma, Greek for monster, is a very rare type of tumor that humans can develop which is capable of producing hair, teeth, bone and complex organs such as eyes and brain-matter, eyeballs, hands, feet and in rare cases it even develops an internal cyst containing a structure that resembles a fetus.
13. In 2002, Antron Singleton a.k.a rapper “Big Lurch” murdered his girlfriend. He was found naked in the street staring at the sky after having cut his girlfriend's lungs out and chewing on them while on PCP.
14. In 1912, a 4-year-old boy named Bobby Dunbar mysteriously disappeared. After an 8-month search, investigators believed that they had him in Mississippi with a woman named Julia Anderson who claimed to be his mother and called him Bruce Anderson, but courts favored the Dunbar Family. He lived as Bobby Dunbar and died in 1966. In 2004, DNA tests concluded he was not a Dunbar.
15. Charles Bonnet syndrome causes vivid hallucinations, but not due to mental illness. As many as one-third of the people who lose their vision can suffer vivid and cartoonish hallucinations. The brain fills in with what it has seen before as the eyes deteriorate. People rarely report them because they're afraid they are losing their mind.
Clinical lycanthropy is a rare psychiatric syndrome which causes the person affected by it to believe that they can or have already shapeshifted into a non-human animal. Patients behave in a manner that resembles animal behavior, for example howling, growling, or crawling.
17. Danny Casolaro was an investigative journalist who was working to uncover a secret group controlling the CIA, White House, etc. Despite telling friends and family that if he is found dead, it wouldn't be a suicide, he was found dead in 1991 after meeting with an unknown source.
18. Epidermolysis Bullosa is a disease affecting a skin-binding protein. It literally causes the skin to fall off with the slightest touch. Children born with the disease are known as "Butterfly Children" because their skin is as fragile as a butterfly’s wings.
19. Human botfly is the only species of botfly known to parasitize humans routinely by capturing mosquitoes and attaching their eggs to their body. The larvae develop inside the skin after falling off the mosquito through the mosquito bite area. They hatch and then the larvae burrow in the skin and eat your tissues until they emerge as a fly that resembles a bumblebee.
20. Naegleria fowleri is a brain-eating amoeba which is found in warm bodies of water. If it gets up your nose or otherwise finds its way into your brain you are dead. Less than 1% of the people with naegleriasis survive. You'll have a high fever, hallucinations, and intense pain which painkillers won't work on (as the pain is coming from inside your brain), fall into a coma and die within 5-7 days of exposure.
Harlequin Ichthyosis is an extremely rare fetal disease. Newborns affected by it have no chance of survival past a day or so out of the womb. They are born with a criss-cross web of red gashes across the whole body and pieces of plate-like scales in between that is actually malformed skin. Also, their eyes are typically solid red masses that bulge outside of the skull.
22. You can pick up Guinea worms by walking around barefoot in stagnant water. They grow to size in your abdomen and then move their way around your body until it feels like they are slowly burrowing through your skin. They then emerge through a blister in the skin about a year after the infection. Then worm then is removed over the course of a few weeks by rolling it over a stick. They can grow up to a meter long.
23. Candiru is a parasitic fish native to the Amazon which the natives believe has the tendency to invade and parasitize the human urethras, where it will stay until surgically removed.
24. Sudden unexpected death syndrome refers to death in which the heart of a seemingly healthy adult just stops for no reason. It mostly affects young men from select Southeast Asian countries.
25. Leishmaniasis is a disease that is caused by a parasite that is spread by the bite of a certain type of sandfly. There are different forms, but the most virulent form can literally cause a giant hole to develop in your face, but only after it turns all of your cells mucillagenous, which is as gross and painful as it sounds.