Feral ghouls, hallucinations, doors that close/open on their own, the tale of a man turning into a mad ghoul and a really creepy altar in the basement.
It gets better. As you proceed through the building, you find numerous audio logs created by Jamie (the aforementioned "man turned mad ghoul") documenting his transformation and Sanity Slippage. The final log contains mostly rambling by a fully insane, ghoulified Jaime—and repeated mentions of the name "Alhazred".
When you find Jamie, he and a number of other mad ghouls are worshiping the obelisk in the building's basement. Once you cross the threshold of the doorway into the cave with the obelisk, you can actually hear a creepy, disembodied voice chanting "Alhazred" repeatedly. If it wasn't obvious already, you can pretty much conclude that the book you're looking for is the friggin' Necronomicon.
By this point in the game you've already seen every kind of Ghoul in every possible situation, yet this area will creep the hell out of you. I kept expecting them to get back up.
A lot of the Dunwich horror (heh) is nice and subtle. Bodies disappearing when you backtrack. Turning around to see that the doors behind you have shut. Too bad if you're concentrating on stalking the ghouls, you can completely miss the scares.
Even if you have the Ghoul Mask on, which makes all the Feral Ghouls friendly to you, that place is still creepy. There's no danger, but the darkness and listening to the history of the residents there is disturbing.
In one room of the Dunwich building there is a terminal with a skeleton laying near it. The terminal tells us that this man who died here was hiding from the ghouls and trying to pass the time while waiting for his friend Billy to arrive with some ammo and grenades. Cue Fridge Horror when you remember the skeleton back at the entrance to the Dunwich building, the one that was carrying 2 ammo boxes...
The room that shows you a brief 2 second-long flashback of what the room looked like before the bombs fell, there's this old guy wearing your average clothes with glasses, computers and office desks in pristine condition, then your character snaps out of it... to see a Glowing One staring at you from not more than 5 feet in front of you.
After the first staircase in the first room of the Dunwich Building, you come across a ghoul who, as you can see if you're sneaking and don't startle it, is on its knees in front of a fire extinguisher's rack - a rack which, mounted on the wall, resembles a cross from his point of view. You might be hit with the realization that whatever was lurking in this building was so terrifying that a feral, 200-year-old ghoul was scared for its soul and, desperately recalling its former humanity, prayed to God for comfort.
Let's talk about the building itself. It stands alone in a small canyon, with no other ruins around it... almost as if it wants to be found and draw the idly curious in. The interior is very dimly lit, making it hard to see Ghouls that are a few feet in front of you. Due to decay, the building is near labyrinthine in structure, with staircases, floors and ceilings collapsed. It also gives a feel as if the space itself isn't right. You have to go up in order to reach the pillar where you destroy the Knivbereh(?)and the exit.
Out of all the terminals in the Dunwich building, only one is NOT rigged to explode as soon as your character touches it. On it, there's a piece of speech-to-text software that also covers onomatopoeia (so the sound of people clapping would go to "//applause!//") which was presumably for recording board meetings. There are logs for six or so meetings stored, the first of which is a fairly standard company meeting. The amount of "//unintelligible//" and panicked phrases increases in each consecutive log after that, with the program recording conversations such as two (or more) people barricading themselves in an office. The final entry reads;
//liquid dripping// Ug-Qualtoth //unintelligible// Ug-Qualtoth. I came, I came. Back this time, deep-temple //unintelligible// screaming, twisting, //unintelligible// //impact sound// No light, no flesh //unintelligible// deep temple born deep temple died. Ug-Qualtoth again, //unintelligible// returned returned //unintelligible// retribution. NOTICE TO USER: Internal memory capacity reached. PagSoft LLC recommends PagMem LLC for all your data storage needs. Please contact your administrator for details.
Another entry example comes from a computer terminal in Dunwich. Voice dictation software has logs of various attempts to use it before and after The Bomb. And during, as evidenced by the software admonishing the user that low-frequency background noise voids the warranty. Low-frequency background noise such as the sound of nuclear explosions. The thought of something recording the event in perpetuity is creepy beyond words.
In Tranquility Lane, activating certain items in an abandoned house reveals a computer console where a wall used to be. This is a lot creepier than it sounds.
And that's for the happy ending for Tranquility Lane.
You step into that clean, sterilized world, and look down at those pods, and all you know is something terribly wrong is going on here - and you're going to have to submit to whatever it is if you want to get your father back. And then you actually get into a pod, the screen comes down, and a face flashes across it - just for a moment - before the needles sink into your head. That's the beginning. That's before you try looking at your PipBoy, and realize just how helpless you are.
Even that tiny detail has been made disturbing: instead of telling the proper time, the watch your virtual self is wearing is permanently frozen. Just like the ones at Hiroshima and Nagasaki◊.
Also in Tranquility Lane; "Go make Billy cry." Sure! "Go break up a marriage." Okay. "Go kill that lady in a funny way." ...Alright... "I want you to take this knife and brutally murder everyone in this peaceful suburb in first person as they run screaming from you." You will end up killing some of them as they hide crying behind their beds. It's just messed up! And somehow, the whole thing being in TV Land black and white just makes it worse.
Don't forget the 50s sitcom music on perpetual loop as you stab.
Even that music is specially creepy. You might have noticed that it has something none of the other songs in the game have - a hard loop break. That is to say, unlike the other music, it doesn't just loop into itself, it restarts. Really sells the "everything is fake" quality.
Worse. Look at your watch, the time is frozen, as previously noted. That means that time does not necessarily flow at the same rate it does in the real world. Now, note that everyone's physical bodies have rotted away. One of them is still a child in the simulation. So how long has it been in there for them!?
The worst part is Old Lady Dithers. She's the only one (not counting you, Braun, and [presumably] "Doc") who is aware of the true nature of Tranquility Lane for some reason (some theorize it's because the memory chip Pinkerton stole from Vault 112 to use in Harkness was from her pod). Essentially, she's trapped in a lucid dream. And since we're not given an explanation for why she knows it's a simulation there's no way to know if she's been lucid for a month, a year, or the entire 202 years she's been trapped in the simulation (meaning she remembers all her deaths and resurrections).
When you get the good ending to the simulation, Betty turns even creepier. How? By switching back and forth from her little girl voice to Braun's old, raspy German accent.
Mirelurks are quite creepy. Maybe it's because they have no necks and their faces appear to be just a mass of stuff. Or how they're always hunched over and shuffle towards you. Or the fact they seem so humanoid at first that they could be mistaken for some sort of horribly mutated wastelander.
To make things even worse, imagine that as the Lone Wanderer, you have (unknown to you) a severe allergy to shellfish. Then, imagine a Mirelurk attacking you and giving you a nice, clean snip on your bare arm and drawing blood. Anyone with a shellfish allergy can tell you that even cutting yourself on a piece of shell can provoke a reaction. A snip from this HUGE radiation filled crab could and likely would cause nothing short of extreme swelling of the injured area, (not to mention your lips and tongue), restriction of your airway and an altogether horrible crawling sensation as histamines work their way frantically through your bloodstream.
To make it worse:
Moira (Literal translation): I want you to go into a Mirelurk's lair where hundreds of them are dwelling, dodge all of them all the way into the lowest level, put a camera in one of the eggpods, then leave and dodge your way back up to the exit without attacking any of them.
The Feral Ghouls from Fallout 3. Especially that noise they make as they run towards you. And just what they are is horrifying...people who used to be sane and rational that were afflicted with this horrible sickness that can't be cured or gotten rid of. They just degenerate unstoppably. Meeting friendly Ghoul NPCs makes it all the worse because you realize that they're going to end up feral. And even if you help everyone else in the Wastes, you can't help them.
Keep in mind, it's been left ambiguous why some ghouls quickly go feral and others from before the War still haven't? Is it a case of genetic factors, the speed in which they initially became ghoulified, further radiation exposure and will they all eventually succumb to that fate? All of the above? The worse theory by far is that going feral has a mental component, that it occurs to those who have simply lost the will to keep on living?
Jason Bright was a feral ghoul who recovered his sanity. It was never explained how it happened, yet he saw it as an act of God. So however it happened, there is hope.
That's not hope, it's terrible! I thought I was doing these poor people a favor with my head-shots - now it turns out they aren't incurable?!
Making things worse, ghouls are quick little monsters. If you're trying to remain unseen, you'll probably keep your Pipboy's light off. But this makes them near impossible to see, so you'll find them running up on you and mauling you before you can get into V.A.T.S. In a dark subway, or a museum, where hallways converge and there's no way to watch your back, it's inevitable.
And then there's the Reavers that Broken Steel adds. Twice the HP of a Deathclaw, twice as fast, deal the same 100 HP damage plus a poison-like drain, throw crippling radioactive gore grenades at range, and occasionally go into an invincible "spazzing" state. Add to that their freakish grinning face and green smoke aura.
Super Mutants, in all their various forms. Imagine walking around D.C trying to find Galaxy News Radio and then out of nowhere a Super Mutant Brute and several Centaurs just utterly dismember you. And that, as Three Dog says, makes you one of the lucky ones! Super Mutants in D.C. don't normally just kill their victims, they drag them to Vault 87, or what's left of it, and then either eat the victims alive or mutate them with FEV.
Taking it further, Fawkes' origin, not to mention all of the horrible things that happened to victims of the FEV virus when they didn't become Super Mutants.
Another example, the mocking laughs of five Super Mutants as a group of captives cries for help. Wait, no, the first four were crying for help. The last one was crying in pain as a Super Mutant gnawed on his arm.
The failed F.E.V. mutants return in the Fallout:New Vegas mod fittingly named Monster Mod: Wasteland Edition. Think they look bad dead? They're alive and angry in the mod.
The freakish abominations that are the Centaurs. See the picture above and add horrible gurgling and the way they move to the list of creepiness.
Wanna make them worse? Well, glitches can do this to you. Running in downtown D.C., followed by an army of Super Mutants, rush into one of the Pulowski Preservation Shelters, which normally keeps enemies out. After a few seconds, a horrible mass of crawling meat can appear in the shelter with you, like it felt from the roof. Apparently, Centaurs can enter in these shelters like they are made of air. Suddenly the shelters don't seem so safe.
Yao Guai. From their milky white eyes, and freakishly matted and balding fur, these things are guaranteed to scare you. Especially if you encounter them when one comes bounding out of nowhere from behind you.
The worst thing about them is they don't make a sound. You could be tooling around in the Capital Wasteland, minding your own business, when snarl rip - you just died. It doesn't get better if you're quick enough to VATS them right before they attack. You swing around to an open maw, ready to eat you.
And then there are the Yao Guai Tunnels, where as soon as you step in, one of them sprints by, without any time to activate V.A.T.S. And they are everywhere.
Somewhat diluted if you have the Animal Friend perk; the super-fast one-hit-killer bears are on your side. They still appear out of nowhere, though.
Hope you don't mind giant bugs. Giant bugs that make skittering noises in dark subway tunnels.
Deathclaws. Super fast, one-hit killing machines. Stumble across one at a low level, and there's almost nothing you can do to stop it.
Deathclaw Sanctuary. Maddening labyrinth of dark, damp caves. Very much like The Descent, complete with lovely piles of skeletons and gore, and pools of blood. Except instead of crawlers, you have Deathclaws. Who move around in the tunnels in somewhat random patterns. Very silently. And when they notice you, they don't run at you screaming...they try to sneak up and jump at you from behind.
In Fallout 3, open the dev console (usually it's '~'), and type in "tcl". That toggles noclip. Now, take out a shotgun and shoot a standing human until the corpse explodes into giblets. Since tcl is on, the giblets (including bits of skull and whole eyeballs) are still in a humanoid shape. This is known to happen as a glitch as well, and the result is...rather disturbing.
There's a place in Marigold station containing a skeleton with a pistol lying next to it. Thanks to the somewhat "overenthusiastic" physics engine, picking up the pistol can cause the skeleton to spasm violently, making it look like it's about to leap up and attack you. For reference, this is in a dark, abandoned subway with creepy music.
Throughout the game, you can find audio recordings made by the Keller family who were planning to hide from the approaching war in a military bunker. However, one of the logs was made by a horrified teenage girl as the bombs were going off. The sound of her panicking and sobbing for her mother through the static can be incredibly heart-wrenching and deeply disturbing.
Two fun follow-up facts: one member of the Keller family was so appalled at the thought of living with his father in a bunker for the rest of their lives that he cheerfully records his good-bye and says he plans on taking a "walk into a mushroom cloud." Also, you can find the family bunker, which contains three skeletons, a Glowing One named "Mr. Keller" and a diary entry (cut from the game but still accessible through cheats) about the father's habit of poking around the irradiated ruins...
Any raider or super mutant base. They seem to love to decorate their home with human corpses. Or parts of human corpses. On spikes. Or in cages. Or chained to the ceiling.
The rigged baby carriage in Fallout 3. An old baby carriage sitting inside an abandoned tunnel which emits baby crying noise when you get near and go KABOOM seconds later. The toy baby inside doesn't help either. And there's also the nice bit of Fridge Horror there, as the cries that the trap makes are exactly the same as the ones you make as a baby at the start of the game.
In Point Lookout, there's a whole warehouse of them.
You may previously have encountered a group of hunters who sell "strange meat", and even give you a free sample. It's really good food! ...and then Andale teaches you what "strange meat" really is. You'll be wanting to find those hunters real soon, and bring your best gun.
Harold's scream if you burn him. What makes it worse is that Harold wanted you to kill him, because he considered the alternative a Fate Worse than Death. He just would have preferred his death to be quick and painless. And what makes it even worse? He's afraid of fire.
During the 'Big Trouble in Big Town' quest, you have to go to an abandoned police station that's crawling with Super Mutants. While there, be sure to check out the computers that have records of 911 calls on them. The one with the woman who can see someone moving outside is positively bone-chilling.
911 Dispatcher: 911, Do you have an emergency?
Woman: Please help me, I think there is someone outside, I heard a noise and it looks like someone is out there.
911 Dispatcher: Remain calm. I'm sending a squad car over, may i please have your name and address for confirmation
Woman: (sound of glass breaking) I think he's in the house now! Please send help oh my god.. I think I hear him!
911 Dispatcher: Ma'am I've dispatched a squad car it should arrive within minutes try (interrupted)
Woman: (sounds of a scuffle)
Man: Sorry for the scare, my wife just (muffled scream) forgot to take her pills this morning. Everything is ok. (long pause) No need for that squad car either. Have a nice day. (hangs up)
Which is the worst possibility? That the above is, as we immediately presume it to be, a case of a police force so apathetic that they let a man break into a woman's home to rape and/or murder her because they just don't care? Or that the pre-World War III world of Fallout was so crapsack that there were enough people going mad with paranoia that police considered it honestly worthwhile to just presume stories like "oh, my wife was just imagining things, she forgot her medicine" are true?
That's just the recording. There is no evidence to prove that the squad didn't just arrive anyways. By that time, though, the woman could be long dead, kidnapped, or raped.
Something about the Animal Friends perk is both scary and saddening. Picture this. You're out in the middle of nowhere, keeping an eye on the map to watch for red blips. Maybe you're trying to get to Oasis, and it's a hell of a trek. You're low on health and have been attacked multiple times. A green blip appears on your radar and you become hopeful. Maybe it's a settlement, a trader, anyone to make you feel less alone. But it's just a mole rat, and suddenly you feel more alone than ever.
And then you'll probably end up killing your molerat buddy and eating its meat to regain health. Sad indeed.
Funny thing, Nuka-Cola Machines (when they make the flickering noise) make the exact same sound as someone slowly walking down a deep, dark subway tunnel towards you, wielding a lead pipe.
How about Ymir beating that bartender to death when you first walk into Paradise Falls? When you talk to him, he's the most cheerful guy in the game! Then you talk to Jotun and find out that that sort of thing is normal. And the body stays there. Forever.
In Fallout 3, every single vault is utterly dripping in Nightmare Fuel. If anything wanted to hit home what a Crapsack World could be and how sinister some organizations can be. The Vaults were essentially the only hope of humanity ever recovering, but were instead constructed as giant social experiments by the government to carry out immoral experiments on live human subjects, with no intention of saving American citizens. Even the control Vaults that worked as they should were for the Enclave to simply see whether humanity could function in a post-apocalyptic world. If you lived in DC you get the choice of being an FEV experiment, brainwashed with white noise, trapped forever, driven insane by hallucinatory atmospheric drugs, murdered by tons of clones or trapped in a virtual worldto be killed again and again. If you are lucky enough you will just be trapped forever but have to endure an iron fisted regime ruled by a paranoid overseer who will kill you if you show the slightest sign of threatening the status quo. If a few hundred years later you stumble across any of the others you might be lucky enough not to encounter any of the horribly mutated or insane residents left or whatever might have moved into the rusted and damaged vaults. Even then you will never ever get full closure on what's happened, only getting the slightest hints as to what exactly went on thanks to journal extracts of residents slowly going mad or about to die. You are probably the only one in the wasteland who has any knowledge of how utterly horrifying things were in there. If the first games offer a small glimpse as to the Vaults' true purposes, then Fallout 3 tore the window from the wall and then swung that window at your nuts for added effect.
Vault 87 dripped with full-on horror - the twisted experiments, the shopping trolley cages - but still found space for a heartbreaking diary log about a guy who loses his son and then thinks he has gone insane when he hears the children from Little Lamplight playing outside, including the son who he thought was killed in the war.
Vault 92, where musicians were secretly Brainwashed by white noise into becoming killing machines.
The only vault in Fallout 3 that isn't downright run down, horrifying, and filled with super creeps is the vault you come out of, Vault 101. But consider the fact that there are all those unaccessible areas, and those radroaches seemed to come from nowhere...
...also, don't forget the lady's poem about how much she hates the Vault.
...and the near totalitarian government used by the Vault.
To put it in more detail, the Overseer is terrifying, one man decides to leave, and does. Causing the Overseer to throw a massive tantrum, kill a suspected accomplice, and alert the entire vault to turn against and murder the escapee's son or daughter, who literally had no knowledge of the escape. Even further he approves of torturing his own daughter to force out information that doesn't exist.
How about the fact that Fallout 3, in its horrific entirety, is actually an incredibly, incredibly optimistic view of the world after nuclear war? For example...there's still buildings. And people. And you can walk ten feet without getting your insides melted by radiation.
Not really, Fallout 3's actually exaggerates the effects that a nuclear war would have. For example, in real life all the trees would have long since grown back, and people would probably have rebuilt shelters not made out of discarded sheet metal. It's a 1950's look on the science of the day, so it's not that realistic.
Except the above forgets this is the Washington DC area we're talking about, that was hit with so many nukes that the White House is a hole in the ground that is still highly radioactive 200 years later. While the 50's take on science is in effect, realistically it's hard for the environment to recover or people to build anything out of more than scrap, when you have raiders and gangs of roaming Super-mutants - some literally as big as houses - armed with massive guns roaming the countryside. While some West Coast areas like the New California Republic have indeed rebuilt, the Capitol Wasteland and most of the East Coast is just one massive warzone.
And even then, it isn't the radiation one should be worried about, it is the drastic environmental changes. Those trees might not grow back because the temperature could end up being completely different than before the bombs fell. Fires would rage so big that they could go on for months or even years depending on what was left after the initial explosions. Soot would cover the ground practically like snow. Hell, you would be lucky if you saw the sun, and there is little chance for crops to grow except in the luckiest areas. There is no doubt: if a nuclear exchange of all warheads was to occur, everything and everyone on the surface of this planet would be dead before we knew it.
Maybe this is why the 'alternate history' diverging around 1951 is used: a post-atomic, badly wounded world is thrilling in a horrible, darkly funny way, while a post-thermonuclear, nobody-here-but-us-deep-sea-bacteria world would bring on Darkness-Induced Audience Apathy.
Even the cut content in the game is pretty freaky. In Fallout 3, there's a house in the town of Megaton called "My Megaton House" that you can turn into your own personal safehouse as part of a quest. That's not the creepy part: the creepy part is its younger cohort known as the "Abandoned House". It's an earlier, untextured version of My Megaton house only accessible via console commands. It has only two floors, with blank, featureless, dimly-lit walls, and only a single chair and bed. Being there certainly feels like it was abandoned not just by people, but by all of reality itself. If you linger for too long, the game crashes. This screenshot◊ is especially creepy. Just that single, heavily-textured and filthy-looking bed in a dark and unearthly-looking room gives this troper the jibblies.
Minor example in Sonora Cruz. Due to the lighting of the Regulators HQ, her face is completely in shadow except for two tiny specs of light reflecting off her eyes. The effect is rather unnerving.
The broadcast towers scattered across the Wasteland can be this as well. Most of them are transmitting a simple message in Morse Code, first sent in the time just after the Great War by survivors holed up underground, but now transmitting on an endless loop ("Hello, hello, this is Echo Foxtrot, are you there? Are you there?" repeated over and over) even after the messages' originators have long since died. Despite this, it feels like a mercy to them to just switch off their transmission once and for all.
This game can be Nightmare Fuel for anyone who lives in the D.C. area and is familiar with the landmarks. Picture this: a nice walk in downtown D.C. and then...BAMBAM you're suddenly fighting a super mutant master with a rocket launcher!
The White House is gone. There's no group trying to reclaim it, no band of monsters holed up in it... It's just gone. And where it used to stand, there's now a radioactive hole. None of the damage to any other area in D.C. is quite as frightening as realizing where the end of the world started.
The Chinese Ghouls you encounter around Mama Dolce's by themselves aren't scary, as much as they're so out of place. That is until Fridge Horror steps in. Said Ghouls turn out to be soldiers and spies from a Chinese covert-ops cell in the D.C. area prior to the War. Not only are these remnants still holding out against the wasteland beyond their old base, but there are hints suggesting that they may still be waiting for orders from China after 200 years. From their perspective, the fact that they can't die and are effectively stranded in "enemy territory" with no chance of returning home could very well be a Fate Worse than Death.
How about the fact that on some level, they've got to be a little resentful that their current condition is due to their own people being one of the nations that fired missiles at Washington during the Great War.
The Steelyard in The Pitt. Especially that slave in the stockades...
There's a bit in the Supply Plant in the Pitt Steelyard where you hear gunshots as you turn a corner. You're at the beginning of a long hallway full of overturned mine carts, and one has a dead Raider in it and is surrounded by dead Trogs. Creepy? Sure, but pretty much par for the course so far. Then a bit further on, you come across the same scenario — dead Raider in a mine cart, dead Trogs all around. How repetitive, you think as you move forward and look down to search the bodies for some loot... then you look up and see that three Trog Brutes have jumped out from behind the mine cart to say hello. Except hello actually comes out as "HAAAAAAAAAAAAAAATE!!!"
In the Supply Plant, there's a closet with a couple of Ingots, a skeleton and a terminal. The terminal spells out a story written by a manager that had to replace his workers with machines (The ones you see walking around the plant). Naturally, the workers were unhappy with that, so they revolt. They try to kill the manager, so he locks himself in the closet. The robots arrive during the chaos. The workers decide to rough the robots up a bit, and that... doesn't go well. The manager writes that all her heard through the night were the sounds of laser fires, screaming and workers begging to open the door. His last entry states that replacing man with machines is always a bad idea. When you log off the terminal, you hear the distant sound of metal clanging slowly approaching. A Protectatron walks by, looks in the closet and simply says MOVE ALONG, PLEASE.
Point Lookout DLC
The small army of inbred swampfolk that basically worship Cthulhu. The Hills Have Eyes, anyone? If you ever see one or two just looking in your direction and doing nothing else, pay attention. Two more are right behind you.
Even worse if you play as a woman; it's probably Gameplay and Story Segregation at work, but there are no female swampfolk. So where do they get more from? That they sometimes sound terribly gleeful about finding you doesn't help...
They also don't...movequite right. Their legs don't bend the right way at the knees, at all.
The hallucination in the sacred bog. They're even more freakish than the entire sum of all of Eternal Darkness hallucinations.
The Schmault-Tec Bobbleheads aren't scary in and of themselves, but they shine a new light and poke fun at the ways the Lone Wanderer must suffer. They mock you, and it's basically your subconscious telling how much being you sucks. The Luck one, the worst of the bunch, tells you that no matter how lucky you can be now, you were already born cursed - to a dying mother and a near-suicidal father in a scarred and ravaged world.
Point Lookout itself is almost STALKER meets Resident Evil 4 meets the Shivering Isles from Oblivion.
The plot of one side quest is disturbing, to say at least, and involves stealing an occult tome from the swampfolk. To elaborate: you can give it to an old man in a ruined plantation. He promptly retires to his basement, filled nearly to the roof with corpses. Or, you can try to give it to some kind of missionary, only to find her dead, with the word "thief" scrawled in her blood on the wall. Her last words tell you to bring the tome back to the Dunwich Building, whose nightmares are already detailed above. At the conclusion to this quest, the entire room catches on fire.
In case you weren't stressed enough, know that the whole place is also bloody Nintendo Hard. That right, even a level 30 perfect character with the Uber enclave Hellfire power armor and the A3-21 plasma rifle will suffer, as in will die a lot if not very careful. Swampfolk and tribals compete with each other for the title of Worst Demonic Spider, and to top it all, if you have also Broken Steel, there will Feral Ghoul Reavers. You just can't feel safe in Point Lookout, ever...
Try going back to the St. Aubin Medical Facility (Underground Lab) after the main Point Lookout quest. This is already after seeing dozens of abandoned mines, POW camps, and serial-killer crime scenes across the swamp.
The fighter jet crash site. All those skeletons... with axes jammed into them... There's just enough information to let your imagination run wild thinking about the gruesome fates of the plane's crew.
The Fridge Horror that no nukes hit Point Lookout - only plague, starvation, fallout and chaos. It devolved to this state on its own.
Tobar's brain room. Especially when you realize he had a scalpel, bonesaw, surgical tubing, and tweezers in his shop from the FIRST SECOND you meet him.
Turtledove detention camp. Depressing surroundings, 200-year-old robots guarding the place, swampfolk and feral ghoul infestation aside, it has a morgue where POWs are taken in, tortured while kept alive by stimpaks, and when they finally die, have their bodies either cremated or jammed into a wall of remains lockers. This all happened 200 years ago. As part of a quest you have to open one of these lockers to retrieve something, and you find a skeleton of a Chinese spy whose picture you've seen on posters all over the place. To see a worn-down skeleton of that person, 200 years later, is rather disturbing. The most sobering part of this camp is that it's likely that similar camps were built during wartime in real life, and people really were taken into these places, tortured and unceremoniously cremated or stashed away into lockers in walls, to be forgotten. Eerily, the in-game example is still scarier because it's all 200 years ago.
Room 1K at the Homestead Hotel certainly qualifies. A room filled with bloody carnage. The bodies have all rotted down to skeletons, but its pretty easy to imagine what the room looked like when the bodies were still fresh. Whats worse is the mask you find in the bathroom, implying that this was the work of the pint-sized slasher; The fact that the room was never cleaned up implies that the slasher did all this after the bombs fell, that he/she was never caught. It's quite possible that we'll find more of the Slasher's handiwork in Fallout 4...
Mothership Zeta DLC
The Abominations. They're like Ghouls IN SPACE!, but with a creepier shout (if that can be believed), and they charge at you with a look of glee on their somewhat human faces.
The alien captive recordings in Mothership Zeta.
Before you actually see anything scary, you hear recordings, including sobbing from a little girl who just wants to go home, a woman describing seeing a human body that looked like it had been butchered, and screams from people who are being dismembered and turned into abominations.
It gets worse. One of the recordings is of a woman whose husband had also been abducted... and turned into an abomination. The recording is of them meeting afterwards. It doesn't end well.
How about the guy who woke up to find his limbs had been amputated? Worse when you remember it starts with him being hit with "something".
Oh man...what did you...why can't I feel my arms...wait...are those...are those my arms? What did you do?! Oh god! Put them back! PUT THEM BACK ON!
Seeing the Alien Workers—unarmed, implied to be civilians—just cowering on the floor, whimpering like wounded animals when they see you, can be unsettling.
Some of the Abominations thank you after killing them. Like were begging to die...
In a rare case of equal parts ridiculous and paranoia-inducing, the aliens have this strange obsession with a robotic toy horse, Giddyup Buttercup. It all seems like some weird, harmless obsession. Then you come across a room where five people evidently died bloody deaths and one of the toys just standing in the middle of it, unmoving. With glowing red eyes. This is just one of a hundred and nine on the ship. Ultimately, the alien's reason for their fascination with them is never explained.