'''Unmarked spoilers below!'''

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* ''TabletopGame/{{Shadowrun}}'''s Third Edition ''Cybertechnology'' sourcebook is a good source of this, particularly move-by-wire implants and cyberzombies. Both are revisited for Fourth Edition in ''Augmentation''.
** The move-by-wire system, like most reaction-enhancing 'ware, is a horrifically invasive implant, but [=MBW=] puts the body into a state of constant seizure and works with conscious muscle control to decrease signal latency, effectively giving the user superhumanly fast reflexes. The downsides are if the control unit is damaged, you have no conscious control over your body's movements and users typically develop [[http://en.wikipedia.org/wiki/Temporal_lobe_epilepsy temporal lobe epilepsy]] with complications (TLE-X), which persists even after removal of the implant. Symptoms include seizures (uncontrolled now) and mood and personality disorders. The only way to fix it? More invasive brain surgery. Yep, really good trade-off for that edge in combat, chummer! Even ''in-universe'', when the MBW system comes up, the runners discussing it are ''absolutely horrified'' at the implications.
** Cyberzombies are metahumans implanted with more cybernetics than their essence can handle, with magic binding their souls to their now-dead bodies. The soul of the cyberzombie ''knows'' that it shouldn't be alive and that knowledge causes them to stop working on a cellular level without a horrific cocktail of obscure magic and medication. Even then, few last longer than a year before cancer and necrosis rots their bodies away and they're almost never even in the same time zone as sanity. A section of ''Cybertechnology'' follows the creation of a cyberzombie: the signature character Hatchetman.
* On the magical side of things is the Blood Mage Gestalt in Aztlan (SR Mexico). At best, they are sacrificing hundreds if not thousands of people yearly "Aztec"-style to keep their President from parts unknown alive. At worst, it's to speed up the return of the Horrors from ''TabletopGame/{{Earthdawn}}'' (see below) to our world. Usually, though, they just kill people to power their spells or to summon spirits into the world comprised of the blood of the sacrificed victims. These spirits would be more than happy to engulf and drown you in that blood, if their master orders it.
** Ritual magic is a fridge horror version of this, period. ''Harlequin's Back'' implies that ritual magic (blood magic or otherwise) causes spikes to form in the ambient magic of the astral plane. Spikes that the Horrors can use to cross. So regardless of intent, the Blood Mage Gestalt is definitely shaving off time before the Horrors start their comeback tour.
** Special Blood Magic spells introduced in ''Forbidden Arcana'' involve inflicting truly {{squick}}y BodyHorror upon caster's targets. Viscera Web, for instance, tears veins out of the spell's target and adheres them to the nearest surface.
* The spell Turn to Goo does ExactlyWhatItSaysOnTheTin: it turns the subject into an amorphous homogenized mass for the duration of the spell, which is thankfully unconscious. This wouldn't be as big a deal if it turned the target entirely; it doesn't affect clothing, gear, or ''cyberware implants''. A lot of popular implants are load-bearing like limbs, eyes, and nervous system augmentations. [[BodyHorror Do the math]].[[note]] For those who don't get it: a popular tactic is to turn a target into a puddle of snot and then pull out their implants, one by one, before ending it. The newly-returned victim promptly dies due to having most of their life-sustaining tech violently ripped out of their flesh.[[/note]]
* Bug City. The Chicago sections of Real Cities is probably the most unnerving part.
* ''Lockdown''. Later books reveal [[AIIsACrapshoot Deus's]] semi-understandable motives for creating that hell, but that does everything but justify his actions for turning an ''entire miniature city'' into a game of ''VideoGame/SystemShock'' with brainwashed slaves and CreepyChild cultists with GlowingEyesOfDoom all so he could live in the physical world.
** Arguably, what happened to the arcology after Deus was destroyed is just as bad: it became low-income housing. There's no funny plothole, because that means ''millions'' of people are stuck there without any hope of advancement, being given the cheapest possible food, water, and clothing, shown only corporate propaganda, with their only chances for money being the most menial labor in the ACHE or ''medical experiments''. And they can't leave. Ever. After all, this is supposed to be a self-sustaining facility, right? Oh, and we almost forgot... not all of Deus's creations were weeded out.
* The first metaplot arc in the ''Shadowrun'' universe concerned the Universal Brotherhood. The Brotherhood was a beacon of hope in a hopeless world, a charity that offered food, shelter, and medical care to the poor and [=SINless=]. Finally, someone's looking out for the little guy! It's too good to be true! It was. The Brotherhood was under the control of insect spirits, using it to gain hosts for more of their kind so they could invade the world. And to build on it, ''Harlequin's Back'' reveals something about the bug spirits: they're the ''advance scouts for the Horrors,'' which is a whole different bag of nightmares.
* In the real world, they tore down the Kowloon Walled City in the 1990s. In Shadowrun, the refugees from the Chinese Civil War ''rebuilt it''. Now it's home to hundreds of thousands of people who have no way out, paying their rent to the Triads because the regular people don't dare go in. Kowloon itself isn't that nice, but the Walled City is so full of suffering and pain that the Yama Kings have manifested and are slowly grinding away at the souls of the people trapped there. The Universal Brotherhood tried to reach out to the people within, but the Yama Kings are so powerful and twisted that they consumed every insect spirit they can catch.
** And [[VideoGame/ShadowrunReturns it gets better:]] It's all intentional. A corp is literally leeching all the good luck, and any possibility of a better life, from every resident of the Walled City. Also, the machine that's doing it for them is slowly tearing a hole in the astral plane. The kind of hole the Yama Kings, and Horrors, can come through.
*** Mind you, the fact that the Yama Kings ''terrify the Horrors'' is awfully telling, as well, when you [[FridgeHorror think about what gives a nightmare nightmares]].
* Bunraku parlors: Yakuza agents acquire pretty girls, either by abducting them personally or through the international slave trade, and have black market surgeons install cyberware that allows the Yakuza to replace their personality with a digital chip. [[SexSlave As far as the customers are concerned]], [[HappinessInSlavery the girls are perfectly happy to be there.]] If the girls are lucky, the chip suppresses their mind to the point of unconsciousness; [[AndIMustScream otherwise...]]
* And then there's the [[EldritchAbomination Horrors]]. You see, there are these things from beyond any world that the human mind can understand, and they feed on pain and suffering. And even the weakest among them could take down a dozen men single-handedly. Thankfully, they are incapable of surviving without a great deal of ambient magic, so... oh. Wait. The world's magical potential has only risen since 2012. [[TabletopGame/{{Earthdawn}} The last time they showed up,]] the only way any sentient life survived was burrowing into tightly-sealed chambers of magical earth. And ''that'' time, we knew they were coming. It's been suggested that Metahumanity will finally develop the magic and technology to beat them before the upcoming Seventh World, only problem is that won't happen for another ''3,000 years.''
** And the only thing that's keeping them at bay for now? ''The Dragons.'' So having no choice but to have someone like Lofwyr have so much power and control as he does over people can be a horrifying thought in of itself.
** There's also one more Horror-related nightmare that the world writ large is unaware of. You know the Great Ghost Dance? That event that brought magic back into the world in a big way? It almost started the Horrors' invasion early, too. It was thankfully delayed, but at a cost. Harlequin was BroughtDownToBadass, and at least one runner is implied to have sacrificed themselves. And this was merely to buy time.
** Here's another bit of awful: the ''Earthdawn'' sourcebooks describe the centuries leading up to the Scourge -- what the reign of the Horrors was called in the Fourth World -- in some detail, including the early signs of the Horrors' arrival. A rough timeline emerges from this, starting with the Fourth World's age of magic already well-established when, centuries in, the first minor Horrors begin to manifest as spirits that drove men to homicidal madness, or that possessed people and turned them into horrific human-insect hybrids. These were rare and isolated at first but became more and more common over an eight hundred year span until the greater Horrors fully crossed through. The kicker is that these early arrivals sound ''exactly'' like ''Shadowrun''[='=]s wraiths and insect spirits -- something borne out by the fact that Harlequin explicitly identifies them as such. These are creatures whose first steps into the physical world should still be centuries away but manifested in full force within decades of the Sixth World's start -- the Horrors are coming, and they're coming ''soon''.
* Fifth edition {{Sourcebook}} ''Howling Shadows'' gives us the [[NamesToRunAwayFromReallyFast Deathspiral Butterfly.]] In short, it [[FaceFullOfAlienWingWong injects its eggs into living people,]] [[ChestBurster who proceed to eat them from the inside out.]] To make matters worse, it injects a painkiller that masks its presence, [[ParanoiaFuel so you don't know they're there until it's too late.]]
* Cognitive Fragmentation Disorder -- the viral form of self-replicating AIs that has made the leap from digital to physical systems. [[TheVirus CFD]] will infect anything more complex than a calculator, including commlinks, cyberware, and biological brains, [[BodySnatcher rewriting the host with its own personality]]. It is 100% infectious on contact, it is incurable by any means magical or technological (indeed, most treatments just make it ''worse''), and as the user starts losing control to [[SplitPersonality a completely foreign intelligence in their own mind.]] These invading personalities vary in intent, but are almost universally hostile to anything that isn't them, and most have no qualms with spreading their infection to make new copies of themselves. It's theorized in-universe that the only reason CFD hasn't ended the world yet is because of it isn't airborne -- yet.
** As of ''Lockdown'', CFD has gone full on ZombieApocalypse in Boston with the new Cerberus Strain. What's worse is that these Head Cases have developed abilities beyond simply infecting others; they have hacking powers similar to technomancers, and can use the nanites in their bodies to enhance their physical attributes, keep conscious after they should be knocked out, resist toxins, resist physical damage, and develop a healing factor that can even regenerate from lethal injuries such as severe brain trauma. The worst aspect is that it's confirmed that the host's mind is never truly erased and exists in an AndIMustScream situation while the virus is in control. The bulk of these head cases are feral ragers and shamblers, but there are more intelligent haters, as well as the hidden, who can pass off as non-infected. And of course, those who had the most seamless transition are now possessed either by the intelligence of a dragon, or by '' '''Deus himself''' ''.
** It gets ''worse'' -- the Cerberus Strain was created to return the mind back to the body of Eliohann, a lesser dragon whose mind was lost in Crash 2.0, as he is the only dragon with a functioning data jack. It's been implied that the Matrix Ghost Cerberus IS the remnants of Eliohann's mind, and a variant of CFD could be used to "infect" the dragon's body and restore his mind. Unfortunately for everybody, the followers of Deus subverted the process and tried to override Cerberus's program in the nanites with Deus. Eliohann's body broke free during the process and took off toward Salem. We still don't know who's REALLY in the pilot seat of the dragon body...
*** Not just any follower of Deus... It specifically was Dr. Penelope Ann Xavier, who's the infamous dissonant otaku-turned-technomancer '''Pax''', the leader of the dissonant otaku tribe Ex Pacis and one of the key players in the GambitPileup that resulted in the second Crash.
* ''Dark Terrors'' is nothing ''but'' nightmare fuel, cover to cover.
** So... remember those bug spirits? The ones that Ares dedicated so many resources to fighting and understanding? Well, if the internal power struggles and the massive dismantling of Firewatch (the Ares special ops group that was fairly instrumental in the effort to retake Chicago) suggest anything, it's that the efforts may have ended... badly.
** While CFD has been cured, it came too late. '''Deus is back''', and might even be able to possess technomancers outright.
** Null Sect. So, you're a technomancer or an AI? The embodiment of the Matrix's sense of preservation sees you as an abomination to order, and will hunt you down relentlessly. They own the laws of the Matrix, can corrupt hosts, and are almost unstoppable once they find you.
** The Dox. Skim a Null Node from a Foundation, and you'll find yourself swimming in paydata -- information literally floats right into your hands. But you pay the price -- over the next few weeks, ''something'' starts following you, harassing you through all digital methods. Fire alarms go off when you're around. The cops keep getting called. Your grocery receipt prints out as a five foot long love poem describing the desire to wear your flesh. It can even follow you to a computer built in the last ''century.'' The only way to appease it is by admitting you "got owned" through an act of supreme debasement.
** Multiple cults to Elder Gods exist, and have powers that break the understood rules of magic in half. What's worse, HMHVV is somehow related; when a group of ghouls is forced to engage in cannibalism, they're possessed by an extraplanar horror, and only sinking the research lab to the bottom of the sea stopped it from breaking loose. By the way, those Elder Gods? It's all but stated that they're the new, copyright-friendly name for '''''the Horrors'''''.
** Asamando. Good ''god,'' Asamando. A country populated entirely by HMHVV infected, their [[ImAHumanitarian food demands]] necessitate keeping massive prisons (known locally as ''storehouses'') of metahuman prisoners, who aren't just killed, but taken apart one bit at a time and kept on life support to keep the meat "fresh." And that's not the worst of it. On top of buying other countries' dead and importing slaves and prisoners to be eaten, Asamando is developing a breeding program. Women are cut down to the bare minimum necessary to carry a fetus to term, and bred until they die. Imagine vast warehouses of nothing but limbless, butchered, pregnant torsos hooked up to life support, with newborns being whisked away to be ''pureed into smoothies'' or raised as livestock. Even this isn't enough -- due to their increasing population, the mysterious increase in the severity of Infected dietary needs, and UN embargo, Asamando is on the brink of mass starvation, which will end with all of those Infected turning to cannibalizing each other... take this into the context of cannibal ghouls becoming a conduit for the Horrors.
*** Two specific things are pointed out in regards to Asamando that are particularly horrifying in terms of their implications for the wider world; firstly, they're extracting numerous specialist from around the world, and as part of the extracting process, they're infecting them by tainting their food. The possibility of this happening in a food processing plant and further contamination causing a massive epidemic. Secondly, Asamando's experimentation into the virus includes attempting to cross the zoological barrier and infecting test animals. The possibility of an infected rat escaping and causing a world-wide ghoul apocalypse is brought up as a very serious concern.
* Tamanous. They're a world-wide criminal organisation specialising in OrganTheft, who are more than willing to kidnap and murder [=SINless=] people for their organs, or just plain harvest them while they're still awake. Any cyberware their victims have gets cut out and sold on the black market as well, with the remains being sold to Ghouls or nations like Asamando. They're also known to [[WouldHurtAChild target children as young as 5-6 years old]], and are actively working to ensure a steady supply of "donors" by running clone banks, [[PeopleFarms fetus farms]], and [[BabyFactory serially impregnating enslaved women]].
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