Dwarf Fortress/Nightmare Fuel

If your fortress hasn't produced some sort of nightmare fuel by the time you're done with you're clearly doing something wrong.

""Wait, how does it intone names without a mouth?" "I don't know, but it still does. That's the creepiest part.""
 * The players. The bloody players. Maternal armor: "It's been a long time now since I realized that dorfs bring their babies into battle with them. It's been a slightly shorter time since I started recruiting only female dorfs into my military, and making sure they each had enough time to mill about with male dorfs to be constantly nursing."
 * "Im beginning to wonder if the goblins arent trying to do the children a favor."
 * Apparently so.
 * The previous comment was in a thread which suggested to raise dwarf children by throwing them into pits with 12 years' worth of food and feral dogs.
 * It should be noted that the children are put into such a situation because 12 years of constant fighting with the feral dogs will, in the event of survival, produce super-dwarvenly tough and super soldiers for instant conscription into the dwarven army.
 * It is possible for a woman to accidentally hit an enemy with her baby.
 * Pretty much everything in the new medical system can cause this.
 * The new health/medical system has had its share of bugs, which is its own cause of Nightmare Fuel. Like your dwarf getting his legs chopped off. Then seeing him still making his way around the fortress doing jobs a few months later, with his legs still missing.
 * Or when diagnostics was still horribly broken and a dwarf would spend literally months lying on the floor bleeding out while the doctor totally ignored him. The solution? Build a spike trap under him and continue to spike him until the doctor took notice of one of his new injuries and dragged him to the hospital or he died.
 * Speaking of diagnosis issues, how about the dwarf whose cut on his leg was diagnosed as rotting lungs? The surgeon then removed the dwarf's lungs...the dwarf, obviously, did not survive. Possibly the worst part? This was an experiment to see what happens when you assign a dwarf with no diagnosis skill to be the chief medical dwarf.
 * Pretty much any player interaction with lava has a good chance of creating this.
 * Bugs especially, as they have a tendency to create things like perpetually burning puppies or unkillable blizzard men who are still wading through the stuff even as their fat boils off through their eye sockets (yes boiling fat is quantified by the game).
 * The cherry on top is that after its over your engravers are liable to fill your entire fortress with procedurally generated carvings of people melting.
 * Tantrum spirals.
 * Procedurally generated Forgotten Beasts and demons in the new version. Say goodbye to plain old vanilla tentacle demons, say hello to acid-breathing carp-elephant hybrids made out of mountain goat blood with four arms and six legs.
 * Unfortunately, the procedurally generated creatures don't tend to be that complex. It's usually a normal animal with one or two unusual feature (three eyes, one eye, pair of wings, horns, etc), a glob of some random material (vapor, vomit, blood, etc) with one or two different appendages (like tails or wings), or a quadruped/biped made of some sort of metal with some extra features (again, mostly tails or wings). Still, some can be quite unnerving.
 * A giant frog-like creature made out of vomit with exposed circulatory system that spits a poison that causes your dwarves' skin to melt and -- thanks to implementation of "syndromes" -- is also transmissible? Geh.
 * A huge eyeless cicada with no eyes and branching antennae and a red exoskeleton that spits webs!!
 * "A penguin brute, who happens to lack a mouth, has a tail, and "it knows and intones the names of all it encounters"."

"A medium-sized monster walking on two clawed legs. It has two mouths on the ends of a pair of tentacles. It uses its mouths to digest its victims with acid and rows of razor-like teeth."
 * The blood of certain Forgotten Beasts causes body parts it comes in contact with to rot instantly. Cue several dwarves roaming the halls of your fortress in a daze, bleeding and spewing miasma as their bodies rot -- while they're still alive -- before they swiftly suffocate and die.
 * Or sometimes they don't swiftly suffocate and die. Sometimes they survive, but all the flesh melts off their feet... but they still have feet and are still walking around despite the fact the rot is slowly moving up to the legs now.
 * Be afraid. Be very afraid. The Ass Demons are out there.
 * A Zinc Quadraped with gas that causes rapid bleeding out. It had to be taken down in hand-to-hand.
 * Sometimes it's possible to get creatures that don't make any sense, like six-legged quadrupeds made of salt that swim in water and magma.
 * A lot of the underground wildlife in the new version, too. Giant cave spiders were bad enough...


 * Some of them are blatant Captain Ersatz versions of Dungeons & Dragons monsters, but many of those are excellent Nightmare Fuel already. Vargouilles/Hungry heads, anyone?

""At this point, we have somehow managed to create * THE* root of evil in the dwarven universe. Here is what it must look like from the mountainhomes: 1) Dwarves go to Boatmurdered and disappear. 2) Lava comes out of Boatmurdered and destroys the surrounding environment no less than three times a year. 3) A maniacal dwarven supervillian comes out of Boatmurdered and goes on a killing spree."
 * Speaking of demons...
 * Boatmurdered. In the end, only one sane dwarf was left, who was wearing both Adamantine Chainmail and Plate Armour to protect him from the insanity. Everyone else was on a murderous rampage or on fire from burning puppy bodies.
 * Boatmurdered was a veritable nightmare fuel refinery. Here's a quote straight from one of the players logs.

"Shit, there are probably entire fucking sagas that are being sung about the evil fortress of damnation known as Boatmurdered.""

""The trumpeting! THE TRUMPETING!""
 * The wildlife around Boatmurdered counts as well:

""All burn..."
 * The Madness Mantra of the afore-mentioned armoured dwarf.

""During the test (a 20 sword free-for-all), a guy got stabbed in the lower body twice, his guts popped out, and then a third guy came up and severed his exposed guts, so that all seems to be working." "In other news, the dwarf with the boiling gold blood...""
 * When you've Dug Too Deep, specifically by, the game makes it very, very clear you're in for some fun.
 * Evil biomes. The werewolves, ogres and masses of undead are bad enough, but hey, you can handle it, even when the fish slither out of their pools like something out of Gyo. Then you notice that all the trees and shrubs are dead, too. Then you notice this doesn't stop them from growing.
 * Savage Evil biomes. They're called "Terrifying" for a reason.
 * As for version 31.19 the Evil biomes became more creepy by sporting grass made out of fingers and Eyes - and yes it blinks at you.
 * Then one of your dwarfs gets possessed and uses some of this 'wood', the bones of one of the 'animals', and a seemingly normal chunk of basalt to make a statue. Of cheese.
 * Occasionally, Toady's comments in the dev log about the more gory moments in testing.

"The wooden arrow pierces through the left testicle! The wooden arrow pierces through the phallus! The wooden arrow pierces through the right testicle!"
 * A recent forum thread (can't find link) was about a player's military encountering a Forgotten Beast that caused their skin and eyes to rot and permanently paralyzed their peripheral nervous system. Thanks to his effective medical staff the majority of them failed to die from either the rot or any subsequent infection. The result was an eyeless, skinless, Legendary military that, thanks to the nerve paralysis, felt no pain. This either belongs here or on the CMOA page. Probably both.
 * This.
 * Dwarf Fortress players are not exactly the picture of sanity, and they're well aware of it. They'll acknowledge how fucked up it is to have a discussion about the best way to capture mermaids in order to start breeding an endless supply to kill and harvest the ever valuable bones from. But they will discuss it.
 * The worst part about this... is that money isn't all that important in DF... DF slowly turns players into Dwarves by having them horde an increasingly valuable treasure for no reason other than they can. Mermaid bones were valuable... but mostly pointless... they did it... simply for the challenge.
 * The worst part is really imagine a scheme to capture mermaids, chain them up and force them to produce young, then "air-drown" the young to butcher them for bones.
 * The best part was that Toady promptly nerfed the value of mermaid bones because he was so horrified by this.
 * There was also the "Most evil/horrific thing you've ever done" thread on the Bay 12 Games forum which was deleted because somebody "won". And it was not the story of the dwarf who broke a child's arms and legs, proceeded to slowly beat the parents to death right in front of the child and then beat the child to death with the corpse of its mother.
 * Just in case you're REALLY curious, it involved
 * How about the injuries?!? When your arm gets ripped off, what do you think? Well, in Dwarf Fortress, Dwarves just keep walking around, leaving a GODDAMN blood trail on the floor. It gets worse in the Genesis mod. They added in genitals. Add in some arrows and you see some messed up combat logs, like:


 * Worse, a well aimed sword swing can cause the parts to fly off in an arc...
 * Oh, and some injuries are nightmarish in themselves. A good sword swing causes your guts to pop out, then an enemy may grab them, bite them, pinch them, or rip them off and throw them in your face.
 * Bronze Colossi. Huge, nightmarishly fast, and unimaginably strong. Oh, and damn near unkillable. Large parties of adventurers have been reduced to screaming, mangled piles of agony by these monsters. They tend to grab their victims, put their limbs in a lock, then break them. The really don't need to: they could kill most players just by grabbing their head, and pinching. Consider that for a second: they could kill you instantly, but instead they toy with you until they tire of you, then kill you.
 * More importantly, they could just strangle you to death (there's pretty much no way you could break their grip), or gouge out your eyes, or many of the other nastier wrestle moves. Instead, they break your arms and legs before punching you to death. They don't blind you, because they want to see the look in your eyes as you die, and they don't strangle you because they want to hear you scream...
 * Battlefailed WAS this trope.
 * Some creatures that were modded in fit this trope quite well, such as the Holistic Spawn from Syrupleaf, as seen here.
 * From Toady One's devlog, with emphasis added: "I tried the butcher command in the arena, and the necromancer managed to raise both a skeleton and a walking hollow skin... which I suppose I'll keep since it makes about as much sense as a walking skeleton. So... keep the necromancer away from your raw skin stockpiles, he he he."
 * This is why vegetarian forts are recommended when embarking in evil biomes.
 * Toady One's devlog is a fountain of this. To date, he has mentioned Dwarves specifically designed with extra limbs (to test item retrieval needs); Dwarves being mutilated on impact while in, and being run over with their innards dragging behind minecarts; the previously mentioned Necromancy... the list goes on and on.
 * A topic on the forums recently was how a dorf baby was killed during a siege and it came back as a ghost. But the ghost baby was still being carried by his grieving mother. Imagine walking down the halls of a fortress and just seeing a mother, in a corner, crying and coddling a cooing transparent baby.
 * With the new release, evil biomes are much, MUCH worse, with sickening sludge raining down from the sky on your dwarves and spreading disease all over the surface, and evil mists that make everything they envelop bleed to death and rise again as a mindless husk. Also, nothing stays dead. Not even butchered animals or severed limbs. Not even if you've already killed them several times. They'll be back again.
 * The new release also bring us lots of Big Creepy-Crawlies, like giant brown recluses and giant mosquitoes that like to swarm your fort and suck your dwarves dry.
 * Also-we finally have something that terrifies the players-which if you've been reading this thread, is really something: Night Creatures. To put it simply: Vampires get a bonus 200 to their physical stats, Werebeasts have a Healing Factor that fixes everything, including limbs, and Necromancers can call a Zombie Apocalypse with a thought. And not one of them ages or gets hungry or thirsty or tired (beyond the vampire's need for blood, of course). Imagine trying to fight these guys.
 * The words "thrall" and "husk" can bring even the most seasoned DF player to abject horror. To summarise, they're creatures that have been turned against life by evil clouds. How bad are they? Oh, they're only so strong that they'll