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* According to the 4th edition of ''TabletopGame/DungeonsAndDragons'', in its ''TabletopGame/NentirVale'' setting, ''every single star in the night sky'' is actually an EldritchAbomination that wants to eat us. Have fun on your next stargazing trip!
** Earlier ''TabletopGame/DungeonsAndDragons'' had a monster called the Cloaker. On the upside, you'll know if one attacks. On the downside, it can manipulate shadows and sound to create illusions (including mirror images of itself), make itself completely invisible, lull you into a helpless torpor, and unnerve you so badly that you can do nothing but cower in fear. All this before it actually attacks...
** Older ''Dungeons and Dragons'' was stuffed full of monsters designed for this - pretty much ''anything'' could secretly be a monster. People learning to be careful about treasure chests because they might be Mimics? Why not greater Mimics that can look like buildings? How about a stalactite or a statue? Or the dust under the bed? Or the floor you're standing on? Any of these could secretly hunger for your blood. It's a miracle people in that world ever took their heads out from under the covers - but maybe it was because the blanket could be a monster too.
** One epic level spell, Demise Unseen, instantly killed its target and gave control of the corpse to the caster that exact moment, with whoever was around to see it none the wiser. Your teammate could well be dead, and have been dead for days already, under control of a powerful necromancer who may have used him to steer you right where he wants you to be.
* ''TabletopGame/{{Warhammer 40000}}'' contains a HordeOfAlienLocusts that eat ''galaxies'' and are slowly but inexorably making their way here.
** Which often home in on signals from scouts that have been established on the target already. Lictors you don't see coming, but they just kill you. Genestealers, on the other hand, implant a tiny "seed" in your body that makes you think you've barely escaped a fight with the 'nids with only minor wounds, so you're completely unaware of being infected.
** Chaos cultists and any other form of subversive anythings are absolutely the in-universe paranoia fuel. Anything that looks like a human but secretly wants to do anything other than die for the Emperor's glory is to be hunted down and destroyed. Hence the various flavors of Inquisitors who would absolutely LOVE to talk about all those disloyal thoughts you've been having...
** Just because we haven't discovered [[{{Hell}} the Warp]] yet doesn't mean we're not going to.
** Ever heard of Noise Marines? If their 'music' ever starts to sound even remotely tolerable to you, your friends will have to kill you, because it means you're falling to Chaos.
** The Alpha legion are infiltration and sabotage specialists, so much so that one Alpha Legionnaire once managed to cause an entire planet to fall ''without setting foot on it'', as the extreme paranoia set off by news of his arrival did the work for him.
** There are many demonic entities capable of complete invisibility and silence, able to hide their existence from all but the most sensitive observers. They could be anywhere, at any time, ready to slash you into bits to please their God.
** Also, you could be (and probably are) serving [[TheChessmaster Tzeench]] and not even know it.
* The ''TabletopGame/NewWorldOfDarkness'' has a good number of examples of this:
** Every thing that exists has a spirit that embodies its core concepts... and this spirit is often a greedy little bastard that just wants power. So, don't be upset if it forces its way into your body, forcibly merges with your soul, and decides to go for a ride...
** There exists a world that is to our world what matter is to anti-matter. Things from that world fall through every so often, eating people's memories and sense of self, just plain eating people, or cutting large chunks from the timeline so that you may have never existed.
** That bench you're sitting on? That rock in the park? That mysterious bit of "modern art" that spontaneously appeared in the square? They could all be ravaging monsters, driven to dormancy by the weight of human observation. At least, until the right kind of person walks by, at which point they'll come alive and won't care ''who'' gets in the way as long as they can get a bite...
** In ''TabletopGame/ChangelingTheLost'', TheFairFolk abduct humans regularly and take them off to Faerie to serve the life of a slave in a dimension of beautiful madness. Sometimes, these slaves escape... but the Gentry have fashioned copies to take their place, which seem like perfect imitations except for the one thing they always miss. So, if your big brother doesn't seem to have that spark he once did, it might not be your brother at all...\\
And it only gets worse if ''you're'' one of these copies. When your "twin" gets back from Arcadia, you have a brief, crushing moment when your identity vanishes and you're frozen by anxiety. Then you start seeing monsters on the street, things that look like men and women but aren't. And then you finally discover that these ''things'' are people who escaped from hell, and who aren't too happy about some faerie's puppet playing make believe...\\
And one more twist of the knife. You want kids? You can't have them; you're a close imitation, but not so close that you can make a new life. But maybe you can... if you're lucky and you truly love the person you're trying to have kids with (oh, and you mustn't know that you're not really human -- AchievementsInIgnorance and all that). The pregnancy will be difficult, the mother mightn't survive, but in the end you've got a bouncy baby... but the baby is going to be a CreepyChild. If you're lucky, it'll be a Fetch-Child; seemingly socially disordered until puberty, able to sense things that normal humans can't, and stalked because of rumors that its blood is poison to TheFairFolk. If you're unlucky, it'll be a Fetch-Spawn; an EnfanteTerrible with no capacity at all for morals or empathy and which cannot be restrained by ''anything''. Lock them in a room? The door opens the moment they touch it. Bind their arms? It falls with the slightest flex. Handcuff them? It springs open in an instant. So you can't keep them in (or out), you can't reason with them, you can't "cure" them, and you live and evade pain only so long as they don't feel like torturing or killing you. And you have no way of knowing which you've had (or even if both types can actually exist in your world) until it's old enough to be able to try and kill you.
*** What about the Changelings themselves? These are humans who have been warped into half-faerie {{Emotion Eater}}s -- and you can't tell them apart, unless you're very lucky. Vampires, werewolves, even mages all have some sort of tell that you can use to spot them. Changelings? Nothing works. Even other monsters are hardpressed to realise what they are...
** [[BodyHorror The Hosts]]... especially spider hosts... Ugh! There are tiny spiritual spiders that want to colonize your body. They will likely begin by ''eating your brain'' until you are functionally non-existent. Then they move in and start colonizing...
** Nosferatu (see Old World of Darkness below) are in the [[TabletopGame/VampireTheRequiem New World Of Darkness]] too. But it gets better: now they aren't ''required'' to be horrifically ugly. Some of them still are, that's just how it goes, but some of them look just like you or me... but when you look at them, there's something... off. Something on a deep level that makes you feel like they're only seconds away from tearing your heart out and sucking the blood from the ventricles. And then they smile, and you wonder why you felt like that...
** The worst paranoia isn't from any of these. It's all of them as a collective. There are monsters ''everywhere,'' they pretend to be human and there's ''no way'' to defend yourself against them. Thank God for [[TabletopGame/HunterTheVigil the Vigil...]]\\
On the other hand, the Vigil has the [[NiceJobBreakingItHero potential]] to [[FromBadToWorse make it even worse]]; that werewolf pack they took out? They could have been the only thing standing between your neighborhood and a bunch of irritable spirits that want to force their way into your world and wear your skin like a new set of clothes.
* In the ''TabletopGame/OldWorldOfDarkness'':
** [[MegaCorp Pentex]]. The company that produces everything, from computer chips to duct tape, that you might come into contact with during the course of modern life -- and makes sure that all of it is in some way designed to destroy your health, your sanity, or your very soul. That hamburger you're eating? It's tainted with spiritual corrosion. That movie you're watching? It's engineered to turn you callous and violent. That aspirin you just took for your headache? It's going to give you something a whole lot worse.\\
Pentex also makes toys that have evil spirits inside. At night and when left alone with the kids they will come to life. Then after several "the child thinks the dolls talk to him" reports, the toy will ''kill the child's parents and blame it on the child''. Bonus points if the child is convinced the toy is his only friend. Have fun playing now, kids!\\
All these products are created by subsidiary companies, so you can't stay safe just by watching out for a Pentex logo, and none of them will (usually) do you any major harm on their own... but every little bit erodes your bodily and spiritual integrity further, and one day you will be past that crucial threshold that will allow an evil spirit to crawl inside of your skin and turn you into an insane, deformed, mutated abomination that will destroy everything you touch during your brief remaining life, and then die messily and painfully. And then, more likely than not, your tumorous body will be ground down by those industrious Pentex folks and used as [[TheSecretOfLongPorkPies an ingredient in the next batch of tainted pizza toppings...]]
** From ''TabletopGame/VampireTheMasquerade'', the Nosferatu: Vampires with unparalleled powers of disguise and invisibility, they take to information brokering like hideous ducks to water. And speaking of ducks, they also control and communicate with animals, and will turn them to their purpose. If your secrets are worth knowing, they ''will'' be watching you, be it electronically, through the eyes of a thousand vermin, or invisibly from the shadows.
** The Technocracy in ''TabletopGame/MageTheAscension''. They have their hooks in nearly as many things as Pentex... and are dedicated to hiding the fact that the world isn't the orderly, static, mundane place they want everyone to believe it is -- in order to try to make the world that place. Which works for you if you're part of that world, but if you see something you shouldn't, or worse yet, by chance end up being ''part'' of the supernatural world they try to suppress -- especially if you turn out a Mage, who they actively oppose moreso than any other element of the supernatural, or a Changeling, who find their mere presence toxic as the antithesis of the wonder and magic the Faerie stand for -- things can get very ugly, and they ''will'' find out. Oh, and remember Pentex above? The Technocracy is ''another'' thing they have their hooks in, so there's a chance that whatever they do to deal with you will wear down your resistance to becoming an unholy mutant, if it doesn't kill you outright.
* ''TabletopGame/UnknownArmies'', as fitting any game about occult conspiracy, is up to its gills in this. Case in point, [[spoiler: fast food workers are magically poisoning you to bend you to their needs.]]
* Indie [=RPG=] ''Exquisite Replicas'' is about an alien reality somehow stealing away things and even people, and replacing them with perfect replicas. Nobody knows why the invaders are doing this, or how, or what the replicated things and people might someday end up doing - if anything. Only the player characters are able to sense the difference and it drives them almost mad with revulsion, especially when someone close to them is taken and replaced. Or the player characters might be mad and hallucinating, and destroying things and killing people for no reason. The idea is based on a real mental disorder called [[http://en.wikipedia.org/wiki/Capgras_delusion the Capgras delusion]], where someone becomes convinced that a close friend or family member has been replaced with an identical impostor.
* ''{{TabletopGame/Paranoia}}'', fittingly enough. You never know when or how your compatriots will try to betray you, on top of the BigBrotherIsWatchingYou setting.
* ''{{TabletopGame/Planescape}}'': Portals. Sigil, the city of Portals, the main setting for the game, is lousy with them. Any enclosed area (arch, doorway, barrel opening, two broomsticks leaning on each other) can be a portal. Portals can lead anywhere, from next door to Hell to a parallel dimension consisting entirely of chocolate. There is no rhyme or reason whatsoever to what portal leads where, the keys that activate the portals can be literally anything, and there's nothing to say that a portal uses the same key to open from the other side. For example, walking through your front door on your way to the supermarket might be perfectly harmless, but coming home and walking through the same door carrying a loaf of bread and twelve apples while whistling "Hail To The Chief" might see you landed on an endless plane of black obsidian with no way to get home.