Heavy spoilers for the game below. Also vampires, ghosts, and other nasties. You've been warned.
The Oceanside Hotel from near the beginning of Vampire: The Masquerade – Bloodlines. Think you ain't 'fraid of no ghosts cause you're a big, scary vampire? There aren't any enemies: You just get to explore the hotel while the ghosts mess with you. Poltergeist activity, knocking on doors, writing in blood appearing on the walls, the ghosts themselves, and the story behind the house add up to a really scary chapter. Do not play with the lights off.
You end up in the hotel's basement, gradually reading newspapers to determine exactly what's been happening in the hotel. You read one that describes how a family was murdered and their heads found in dryers, and then you put down the newspaper and the door to the dryer right next to you creaks slowly open... Theres a sound that's triggered when one puts that particular paper down, like a pair of shoes in, well, a dryer...
In the basement is a crossroad of corridors with rooms. As you approach that middle point where you can turn down any of the four paths, a screaming woman rushes by, panicked and looking back over her shoulder at something chasing her. If you look to the direction she was running from, you see nothing. If you look at the direction she ran to, even if you got there just after she passed out of sight, she has disappeared.
The charming picture of said family with the father drawn as a burning demon, after which the words "GET OUT" are carved into the wall in front of you.
The game does give you some credit if you manage to steel yourself, though. For instance, after said dryer door opens, you see that the other door is selectable...and you really, really don't want to open it and see what's in there. If you do, you thankfully find the keys to the room where you can turn the electricity on.
Right after you run through the hotel's kitchen wherein a poltergeist completely scares you by suddenly launching every un-nailed-down object at you and making the ovens burst into flames, at once both shattering your ear drums and assaulting your character with damaging effects you sneak down a hallway to a completely normal room. As you climb out of the vent to land in it, you hear a girl whisper: "Run..." and...well, if you don't run to the other side of the room and quickly begin climbing the ladder,you get smashed by an elevator.
Towards the very end, you enter the master bedroom, the whole scene shifts to a flashback of the room back in the fifties or so, you walk across the clean room, and retrieve the amulet you needed to find. The flashback ends, and you're standing on a platform in the room, and it's revealed you've just somehow crossed a broken, skeletal room with no floor.
The part where you go to the left side of the hotel in typical explore mode. You turn around and there is an Ax-Crazy ghost murderer right behind you. There might have been a scream. And the sudden exploding lamps and vases only add to the terror. "He's here..." Cue flash of ghostly cowboy looking silhouette...wielding an axe. Yeah, thanks for that, ghost lady. Can vampires have heart attacks?
This is a blink-and-you-miss-it moment, but when you first get to the generator room, if you look between to two huge pipes that stick horizontally out of the wall, you can clearly see a man holding an ax in his hands, then when you walk around the pipes, he's gone.
Or he appears to be holding a severed arm. And if you don't blink, you see he turns to the side and starts slowly walking. To the corner. That leads to where you're standing.
As soon as you enter the Hotel, if you look to the right, the ghost will be standing right there, watching you, with his axe in-hand, but immediately after he enters your field of vision the light above him flashes and he disappears.
Don't use Auspex while in Oceanside. Just don't.
Alastair Grout's mansion. Filled to the brim with bloodthirsty lobotomy patients, more Malevolent Architecture than you can shake a stick at, not to mention a truly epically creepy background tune interlaced with the monologues Grout left on tape that showcase his spiral from mere sociopathy into true paranoid schizophrenia.
The female patients with the masks. You enter the mansion, and you see one of them in a corner, and you can't tell if she's crying of laughing. You come closer to help her, and suddenly she attacks you with a knife. And throughout the whole level you can hear them. The laughing. The laughing. It drives you mad!
The More Fun With Pestilence side quest, where you investigate the base of a cult that's been spreading disease all over the place. Turns out, the guy in charge has been infecting his acolytes and turning them into mindless, brain-eating zombies. You end up finding yourself desperately hacking your way through through a literally endless horde of zombies in a dilapidated, run-down building while getting lost in the labyrinthine corridors. Oh, and unlike the bloodthirsty lobotomy patients, these guys don't just attack you. If they get too close, they'll latch onto you and start chewing through your skull to get at your brains while their friends take turns ripping pieces out of your helpless form.
The section of the game where you investigate a snuff film. The subject is bad enough. Then they add the screechy music from the hotel sequence and then have warped human husks composed solely of arms grafted to a snarling, fanged head running around trying to eat your face. Then you find the mansion where it was filmed. Wallpapered in human flesh.
That horribly distorted "Kill!" as they suddenly jump from 10 yards away straight onto you.
The fight against Ming Xiao's true form: a horrible gelatinous blob that can spawn copies of itself.
That raptor statue in the corridors of the Museum, which is realistic and just behind a corner. It was lampshaded by a member of the staff too. This moment is even creepier if you spoke with the Seer on the beach and heard her little rap about seeing dinosaurs, and her sudden spiral into absolute terror when she cries "It's open... Oh god... It's Open! Run! RUN!!!"
The Abandoned Hospital downtown. As you enter, you meet a guy who's scared out of his wits by what he's seen in the basement. The descent to to the basement is as creepy and atmospheric as an Abandoned Hospital with an unknown horror waiting for you should be... then you find out what he's scared of: a vampire who actually has to eat her victims who killed the rest of his reality TV crew and needs him dead to preserve The Masquerade.
That vampire also says , "True terror is not the sight of death, but the fear of it." The player advances through a scary hospital, constantly expecting to die a horrible death. Then you find a friendly quest giver NPC surrounded by bloody corpse bits, and in the end she's not that bad.
Finding the Nosferatu in their sewer hideout, and face the above mentioned grafted horrors, as well as spiderlike abominations made from a woman grafted to two other bodies that crawl out of the vents in the sewers to eat the dead workers' bodies, while in the background the music seems to form words: "Helllp meee...voices won't leave me alone..." Even once you get out of danger, it's still freaky—a voice from somewhere you can't see that sounds like a deranged little girl whispers to something about staying out of sight.
One of those women grafted together? Yeah, she was pregnant, her womb is cut open and the fetus has been stolen When you consider the guy who did this it becomes even more scary.
The werewolf chase towards the end of the game. You're up in the mountains, believing that this is just a simple meeting with Nines. A short while later, the sight of a forest fire starts to freak Nines out. If you inquire as to why he's scared, he tells you that the mountains are werewolf territory, and that the fire was probably set to drive the werewolves towards the two of you. Nines then gets bowled over a cliff by a werewolf, and you have to deal with another. By this stage of the game, you've probably picked up some heavy-duty weaponry like the flame-thrower of automatic shotgun. They do nothing. What follows is a nerve-wracking chase through an abandoned observatory, with a mountain of teeth and claws right behind you the whole time. You will doubtless find yourself whimpering a bit as the chase progresses.
Perhaps the most frightening thing about the werewolf chase is that even the game's cheat codes are useless against it. If you go into the console and turn on the invisibility and invulnerability cheats (notarget and godmode, respectively), it can still see you and hurt you. Whatever keeps the invisibility code from working on it also keeps Obfuscate from working on it.
Pisha mixes between this and Fetish Fuel. The way she slaughters a reality TV show crew while the player characters are helpless to do anything but watch. Pisha's attractiveness only makes it more unnerving. Her pleasant demeanor and voicework by Mary Elizabeth Mc Glynn either hurt or help the fuel.
Certain portions of the Grout Mansion. Specifically, it's a mansion filled with tortured and insane people kept in Hannibal Lecter-esque masks. They've been driven totally mad by Grout and there's nothing that can be done for them but send them to a horrifying grave. That doesn't even include all the other horrible stuff that Grout is keeping there. Such as his dead wife's perfectly preserved corpse.
And the reason the wife is a corpse might very well be because Grout decided to remove her entire brain for study. Nightmarish and insanely sweet and sentimental given all the other objects surrounding the body were supposedly objects from their courtship. The fact that Grout is trying to "cure" her is probably his Malkavian insanity manifesting. Might even count as Heartwarming when you consider that Grout considered his wife's Mind/Brain important to him. For a man born and embraced during pre-Freudian era, it was quite a progressive attitude.
And it's not helpful later when Bach sets everything on fire and the ghouls are now flaming.
The ghouls are particularly nasty creatures by themselves. They're moaning, inhuman, and monstrous things that look closer to Nosferatu than humans. The idea this could be the fate of people like Mercutio or Heather is a disturbing one.
The player character can be this as a Nosferatu. The other characters in the game seem to think so.
Or Malkavian. Some people find the happy Malkavian outfits make their attacks with fire-axes and severed arms all the more frightening. More than the outfits, their "Dementation" dialogue options are freaky. Seriously, you can make people do whatever you want, usually by driving them mad. A bit of flavour text from the Dark Ages rulebook is appropriate here. "Dominate might erase your memories, Vicissitude might reshape your form, but Dementation can destroy your soul."
Again in terms of Disciplines, Suicide and Mass Suicide, which both force your enemy/ies to choke themselves to death.
Malkavian's Vision of Death. It kills. And there's nothing the victim can do to save himself....
Andrei the Flesh Crafter's house on King's Way is made and furnished out of people. And the "furniture" might still be alive and aware of what they have become. Time to break out the flamethrowers and Mercy Kill the poor house.
Mitnick. Unless he's lying (though in a Old World of Darkness setting, probably not), its very likely that the geeky, cheerful little Nosferatu potentially has more power to cause horrific death, destruction and suffering on a scale that surpasses practically everyone in the game (or perhaps even the entire World of Darkness) up to and maybe even beyond Caine himself. How so? Even as a mortal, Mitnick was able to anonymously obtain nuclear launch codes and sent them to the President. For fun. Now that he caught the attention of the Nosferatu and has been embraced, he's potentially immortal, has access to what he calls "cool toys" and a secret, possibly eons old and globe spanning information network to play with.
Also a spot of Fridge Brilliance if you had Becket talk about Gehena: "A mundane apocalypse is much more likely that a supernatural one."
In the Nosferatu Warrens, you begin hearing whispers - whispers like the Malkavians usually hear, but you hear them regardless of what clan you are. Are you going crazy? No. Once you talk to Gary Golden, you realise that every Nosferatu in the city lives in those warrens, and most of them are invisible. From the very moment you stepped into the warrens, you were surrounded by them - and you couldn't even see them. Those whispers you hear? They're close enough to whisper directly into your ear.