[[folder:Classic series]]
* ''VideoGame/{{Doom}}''... Demons everywhere, but maybe turning them into LudicrousGibs is even scarier.
** From the demon's perspective? YOU. They were slaughtering everyone in seconds a moment ago, and here comes the lone survivor, a guy who punched his superior officer to death and fell asleep before you invaded.
*** Also further to note that the Doomguy is proportedly the only survivor of using the berserk packs- and uses the entire box of them. A single one of them is enough to kill someone. And he could probably punch his commanding officer to death in a single hit, and gib them much like the demons.
* The face in the HUD also keeps getting bloodier as you take more damage. In some versions, a big hit when low on health makes the [[YourHeadASplode head explode]].
* You've defeated the [[BigBad Spider Mastermind]] and in the act proving yourself too tough for hell to contain, so the demons give you an easy break and open a portal to let you back to your home world. Cue a grassy field with golden skies and a bunny, [[spoiler: Daisy]], roaming around to a blissful flute-and-birds tune. The screen then scrolls and the tune becomes more off-key, distorted, and evil as a burning city comes into view and ''the bunny's severed head is impaled on a spike''. For those who played the original versions of ''Doom'', this was the ''end of the game''!
** The [=ZDoom=] and [=GZDoom=] source ports supports mouse for the menus, and it uses Daisy's severed head ''as the default cursor''.
* The Spider Mastermind. A creepy-ass demon with a brain that's far too big, on a mecha platform with four spider-like legs and a powerful chaingun that will tear you apart if you're too close.
** And in ''Doom II'', you find out that Spidey is a mommy -- and her little Arachnotron babies are every bit as bad as her with their plasma guns.
* In ''Doom II''[='=]s map "Dead Simple", once you killed all the Mancubi, the walls would come down, surrounding you with hordes of Arachnotrons.
* At the end of the first major episode ([=MAP11=]) of ''Doom II'', the room containing the master control switch has walls entirely comprised of stitched together corpses.
** In the same map, upon grabbing a key you have a first encounter with the most powerful non-boss monster in the series, the Archvile, an incredibly fast and tough skin-and-bones humanoid that towers you and can easily resurrect the demons you used up so much lead to put down. It also roams around with a deep, evil laugh. And then when it attacks you, you better hope you find cover before the flames covering your screen flicker out...
* The "pantry" you encounter near the end of ''Doom II''[='=]s [=MAP27=] (Monster Condo), which is filled wall to wall with hanging and skewered corpses. The level's eerily somber music makes it that much worse.
* Despite their relative weakness compared to other monsters, the noise made by former humans as they wander around is quite disconcerting.
* The scream the BigBad of ''Doom II'' makes when you fire a rocket [[spoiler:into the hole in his head that the monsters come from]].
** And that's only the half of it: as soon as the noclip cheat reveals the [[EasterEgg True]] [[Creator/JohnRomero Big Bad]], whose head is actually residing in a small room, while its' hanging on a stick... Hey, the hint to the beast's real identity is even here, in his only spoken quote ([[SubliminalSeduction consider reversing that]]):
--->''Oremor nhoj, em llik tsum uoy, emag eht niw ot...''
* [=MAP05=] of ''TNT: Evilution'' qualifies as Nightmare Fuel and makes the developers into {{Magnificent Bastard}}s. The level starts in a thin hallway with other, shorter ones protruding out from the sides. Walk to the end of one hallway, the wall behind you opens to reveal ''another'' hallway, this one filled with monsters. Clear them out, go down the next hallway, sequence repeats. When you go down the third hallway, you've probably caught on by now, so you go down that one backwards... and then ''the hallway extends'' and you ''still'' get ambushed from behind.
** [=MAP11=] from ''The Plutonia Experiment''. Start off with the music from the ending of the original game, see a backpack and a switch in the room ahead of you. And then you look to the left and see a ton of Archviles frozen in place behind a fence -- and when you hit the switch, they un-freeze and teleport out into the maze you're just about to enter. The level is quite fittingly named "Hunted".
* It's bad enough that the red key maze in "Halls of the Damned" ([=E2M6=]) is nearly pitch dark, but it gets worse when you realize that it's dotted with {{Monster Closet}}s, which open with no warning.
* The side maze that eventually leads to the [[spoiler:chainsaw]] in "Nuclear Plant" ([=E1M2=]) is very dark with fairly erratic lighting, along with the unsettling moaning of former humans as they search for you.
* The final level of the first episode of ''Doom'', "Phobos Anomaly", ends with your marine stepping on a teleporter that plunges him into a black abyss where you are constantly losing health either from simply touching the floor or being assaulted by a barrage of barely-visible monsters. You stay there being ravaged by these things until you run out of health, at which point the next episode begins. It truly becomes nightmare fuel if you only have the {{Shareware}} version as this is where the game would end, leaving you to wonder what exactly happened to your hero when he stepped on that teleporter.
** The level itself is very unsettling. It's dark, the music is creepy, [[NothingIsScarier there are no enemies to be found]] (at least on lower difficulties), and you start in an area filled with ammo and power-ups -- which makes it pretty obvious that a big fight is coming up. Then you take an elevator up into a big pentagram-shaped room and are greeted by a loud, scary demonic roar as two of the biggest and scariest-looking creatures you've encountered yet appear to fight you.
* ''Doom 64'' remains less well-known than ''Doom'' and ''Doom II'', but it manages to take the classic ''Doom'' gameplay and make it much scarier, with darker graphics, more muted and grim colors, and one absolutely creepy soundtrack. Gone are the heavy metal-inspired tracks, replaced by [[http://www.youtube.com/watch?v=OdzgSNFlhc4 incredibly]] [[http://www.youtube.com/watch?v=q0wiXQMTDdE unsettling]] [[http://www.youtube.com/watch?v=g07rCtrlwn4 ambient]] [[http://www.youtube.com/watch?v=M30LlWFYZqo music]]
** And those aren't even the worst of it. You want the definition of unsettling ambiance? Here's the theme for [[https://www.youtube.com/watch?v=gsZP80NKbBA Breakdown]]. Have fun sleeping tonight!
** The Pain Elemental looks rather cute in Doom 2, but in Doom 64, they are much worse to look at. They have two mouths on either side of their body and summon two Lost Souls at a time. The souls charge at you constantly and can overwhelm by sheer numbers and kill you alarmingly fast if you're careless.
** The [=PlayStation=] and Saturn versions of ''Doom'' are no slouches either. Like ''Doom 64'', the rockin' music has been replaced by a dark, creepy, and unnerving soundtrack from the same composer. The [=PlayStation=] version goes the extra mile by giving these games a much darker atmosphere with its colored lighting.
* So many of the wall textures are downright creepy. There's giant stone demon faces, red-eyed horned gargoyes (which sometimes spew blood from their mouths), scrolling walls made of distorted, anguished faces, switches that look like laughing harlequins... and that's not even getting into the MeatMoss walls.
** In the Suburbs level of Doom II, there's a house where one of the gargoyle faces is behind a wall that covers the entire face except for the eyes. Just two glowing red eyes, eternally peeking into some guy's living room.
* Soul Sphere contains a haunting, silently pulsing face, implied to be an actual trapped human soul.
* [[http://www.youtube.com/watch?v=uF2n-IoE51g Title theme]] from Doom II is a creepy, chaotic melody that sounds like something from classic slasher movies.
* [=E1M5=], Phobos Lab. The level itself really isn't that unusual compared to other levels in the episode, but as its background music, it has the aptly-named [[https://www.youtube.com/watch?v=FMex4f8cwEY Suspense]]. The four (or five, if counting the secret) maps before this one had upbeat tunes fitting well with either run-and-gun shootouts or action-thriller standoffs. Then this song comes on, fully intent on scaring your pants off. The kicker? This map is the setting of the first title screen demo in every version of the original Doom. Imagine being a small child and seeing it (and the demo player's inevitable demise) as one of the very first things upon booting the game up for the first time.

[[folder:Doom 3 and expansions]]
* Dr. Malcolm Betruger. When you see him the first time, you immediately get this feeling that there is something...odd with him, just by seeing his inhumanly pale skin, his permanent sneer on his lips, and his glassy and fishlike eyes that yet seems to burn with fierce hatred toward everything and everyone around him. His raspy and aging voice filled with venomous contempt only reinforce that feeling, and generally, you get this foreboding sense that he'll be behind much of the troubles you'll face. At first, you may think he'll be just the generic MadScientist doing unethical experiments ForScience, but no. Turns out he's even worse than that: he's a Satanist who has made a DealWithTheDevil, and with that deal he has become an omnipotently being who [[ParanoiaFuel always knows where you are or what you're doing, watching you like a falcon watching a mouse from the sky]], and that's what you feels like when he sends waves of demons at you while he taunts and laughs at you seemingly from the walls. The fact that we know almost nothing about his backstory only reinforce that fear.
* Your first teleportation. Welcome to Hell.
* After Hell invades, go to the bathroom in first part of the game and look in the mirror. A JumpScare follows as your face momentarily turns demonic and the camera zooms in on it.
** The Xbox version moved this one to near the end of the game, after you think the game is done pulling s*** like that. Not a pleasant surprise for people who think they've finally gotten a handle on the game.
* Cherubs: Babies with wings and lower bodies of insects, often traveling in swarms and making creepy baby sounds.
* The Trites are flesh-coloured spiders the size of sofa cushions with an upside-down human head instead of a body, with eight black eyes to make extra sure you don't get any sleep. They weren't ''too'' bad for most of the game but there was a JumpScare late in the game involving a touch-screen computer and a nice dark compartment behind it for a Trite to hide in.
* At one point in the game there was a flight of stairs with a landing covered in blood (the walls, the floor, just drenched with it completely). By this point in the game that seemed like absolutely nothing. But when you walked out onto the landing what appeared to be a face suddenly appeared on that blood covered wall.
* The introduction of the Lost Souls. Before you fight them, you hear a woman crying. When you see her, she weakly tells you to help her and she turns around. You get to see her skin greying and her skull forcibly ripped from her head along with her spine.
* The scene where bloody baby footsteps appear on the floor, and a ghostly voice implores to "follow me" and "hurry". Eventually, it says "they took my baby", and the screen turns red for a moment as creepy baby cries are heard.
* Near the start of the game there's a segment where you're crawling through an air duct, when all of the sudden a ghostly voice whispers "Help me!" and it sounds like it's right next to you. If you happened to be wearing headphones the first time you played that part you probably didn't sleep with the lights off for a while.
* Upon traveling through the first part of the Communications Facility, you come across a door drenched in blood, with dark red streaks across it. When you first open the door, a demonic face bursts through the fleshy wall behind the door and growls hideously, before receding back into the folds of the flesh, as the door closes permanently.
* What might be a huge shock to players is that using your PDA doesn't pause the game, it pauses ''you''. You could be checking your e-mails and all of the sudden hear rapidly approaching footsteps...
* "Death will not be your end. Your soul will burn in Hell forever." (shudder)
* Early on, just when stuff is getting nasty, you turn a corner to see a ventilation shaft spit out body parts.
** Much later, you have to traverse a nasty area, with your only light the glowing tube of a demon on rails. That's right, your flashlight is running away from you.
* One of the first encounters with the new-style imp is this. You can just make out some glowing eyes under a set of stairs, and for veteran Doom players, this is an obvious trap. However, the imp then [[spoiler: bursts out from under the stairs without using a door.]] To all of those who used to use the environment to help avoid enemies, this new ability to ''manipulate'' the environment by the monsters is a an absolute shock.

[[folder:Doom (2016)]]
* The much greater detail in which we see blood-stained walls, and eviscerated corpses littered everywhere.
* The ambience soundtrack.
* The Revenant's [[HellIsThatNoise shrieks]], period.
* The footage in the single player demo shows a security hologram of a Hell Knight ripping an unlucky [[RedShirt Red Shirt]] in half before smashing a computer technician into the keyboard, crushing him, before turning around and snarling. Pretty good way of setting up the creepy atmosphere.
* While the Doomguy's executions on the Demons qualify as moments of awesome, the ones we see from the end of the Campaign trailer and single player previews are this trope incarnate.
** First, [[spoiler: the Revenant leaps on you, [[AnArmAndALeg '''pulls''' both of your arms off]] (with all the delicious sounds that accompany it), smacks you twice with the right arm, '''cracking your visor''', and then the screen smash-cuts to black as the Skeletal demon presumably punches through the visor. What's worse? This moment is accompanied by [[PsychoStrings Psycho strings.]]]]
** [[spoiler: The one revealing the Baron of Hell. It leaps up with a demonic roar, smashes you to the ground, then takes a moment to leer at your futile attempts to crawl away, before stepping on your torso with its gigantic hoof, grabs your legs, and '''[[HalfTheManHeUsedToBe tears your body in half.]]''']]

* ''VideoGame/BrutalDoom'' [[NightmareFuel/BrutalDoom has its own page]].
* Less so with the original ''Doom'', but the ''Film/{{Aliens}}'' custom mod is certainly scary. When you're holding a Pulse Rifle, and there's a dark corridor lit only by a sporadically blinking light, and you hear strange sounds coming from potential corridors in that darkness, willing yourself to press the "forward" key is an exercise in futility.
* [[http://www.youtube.com/watch?v=qkMonYgb_i8 This]] is a video of a grown man screaming like a little girl while playing the ''Doom 2'' mod ''Ghoul's Forest 3''. ''Ghoul's Forest 2'' and ''3'' are quite possibly the most terrifying mods for ''Doom 2'', for that matter. The entire concept is that you're hunted through a dark forest by giant floating super-fast monstrous heads who pop up unexpectedly and kill you in seconds.
** The backstories of the ghouls are creepy: the BigBad Yurei is [[StringyHairedGhostGirl the ghost]] of a pissed-off girl who was abandoned in the Forbidden Forest. The Creeper is the spirit of a baby, the Sjas was a psychotic jester who was executed by the king for a certain joke, the Jitterskull was a [[ProudWarriorRaceGuy Giant warrior]], Choke was his demented brother who killed himself. Frostbite (who only appears in the multiplayer mod ''VideoGame/GhoulsVsHumans'') died of frostbite, so now he can breathe ice and swallow people whole like the Jitterskull.
** The Yurei is an interesting villain, in that she attacks you by making [[ShockSite disturbing images]] pop up and take the entire screen, with [[HeroicBSOD predictable results for the player]]. Yes, that's right, a boss who directly assaults the ''[[TheFourthWallWillNotProtectYou player]]''.
** The mod is made worse with Icy's addon, which adds a clown; a skull that makes the Jitterskull look like a joke; and a Sjas-like mist cloud that is absolutely relentless. These new ghouls use the terrifying creeper scream. There's also a chance that, instead of the Yurei, the final boss will be the entire cadre of ghouls at once.
* The Skulltag ''Armageddon 2'' multiplayer map pack is infamous for the "By Day, By Night" level. It's a map that alternates between day and night. By day? Cheerful demon massacring, upbeat music. By night? The entire map goes dark, the music turns into horrifying loomy ambient, and the monster are... ''different''. And the Eyesores appear. Eyesores are ghouls, just like the ones in ''The Ghoul's Forest''. Imagine a demented, deformed face on spidery legs which runs around like it's on crack, makes weird "kekeke" sounds and can kill you in seconds. And there's an entire crowd of them attacking you all at once.
** The final boss of the map: Clowny. An invisible face which flies around the entire (big and open) final area and pops up suddenly in front of a player for an instant-kill and a JumpScare. And sometimes it somehow ends up inside the mazelike building you've been in before, forcing the players to brave its silent corridors, expecting the bastard to jump out from behind every corner...
* The ''Happy Time Circus'' series is the very definition of horror, especially the second one. Wandering through an abandoned ghost town with lots of silence and empty moments, only to have an area completely enveloped by {{Monster Clown}}s that you may or may not be able to handle? OhCrap...
** The areas that take you through Clown Hell (which is also slowly encroaching on the town itself) are no less horrific. Bright, cheerful, flashing colors in extremely low light conditions produces a highly unsettling effect, and the heavily distorted circus music sometimes heard in these places doesn't help one little bit. And as you might have feared, [[Literature/{{It}} Pennywise Itself]] makes several appearances throughout both mods, along with It being a boss-level monster in the first one and '''the''' boss in the second.
** In the midst of all this, you'll also need to escort "Fluffy" back to Clown Hell. Fluffy is a fast-moving, unkillable severed rabbit head that can pass through walls to [[PersonalSpaceInvader chew off your face]], and you have to outrun him through a narrow passageway in a dense thicket where the tiniest misstep will allow Fluffy to gain on you. Good luck, and keep some extra underpants; you will most certainly need both.
* The ''Equinox'' mod, at first, might make you do a double-take when you realize such a well-made mod is from the same guy that made the infamous "nuts.wad". Then, about map 13 or so, you infiltrate an alien space ship. It is incredibly dark, very cramped, the music is creepy, and it is ''filled to the brim with Arch-Viles''.
* ''Unloved'' is the mod that you always wanted to play but hoped no one would ever make: it's a high-res megawad that borrows much of its atmosphere from the ''SilentHill'' series and it's exactly as terrifying as that description would suggest -- while preserving the run n' gun gameplay of classic DOOM. If you ever wanted to prove people wrong who insist that horror games should be weaponless, this .wad is it. [[note]]Using the source port GZDOOM is highly recommended to play ''Unloved'', as other source ports do not offer the lighting effects that set the perfect mood and can lead to severe NightmareRetardant from the hundreds of brightly-colored "!" sector flags they leave visible in the game.[[/note]] Highlights include a dank, extremely gory prison/torture cellar decorated with grotesquely mutilated bodies and bloody faces stretched over frames like canvas, a gloomy series of corridors and cageways suspended over a black void that could have come straight out of ''VideoGame/SilentHill3'', and a stage called "The Living Room," which is [[WombLevel precisely what it sounds like]].
** Even better (or [[GoneHorriblyRight worse]]), Unloved has now been spun off into its own game (by the creator of the original mod) rendered in Unreal Engine 4, with completely new and grotesque monstrosities to replace the old ''Doom'' sprite monsters and a procedural level system enduring you'll ''never'' feel safe and comfortable. Those of you who found the atmosphere and design of the original mod disturbing but just couldn't get past the dated mid-90s sprite graphics, rejoice... or despair.
* While the first ''The City of the Damned'' map is plenty spooky and atmospheric enough, the second installment "Apocalypse" is more horrifying in every possible direction. Imagine the game ''VideoGame/{{Blood}}'' with all elements of BlackComedy stripped out, now add in chilling {{Apocalyptic Log}}s scattered about that tell the story of what happened to the town and several frightening scripted events like the ominous sirens that sound off now and then. The creepy soundtrack to ''VideoGame/ResidentEvil3Nemesis'' is also put to very good use throughout the mod. Oh, and those sirens? When you hear them, stop what you were doing and get to a shelter. FAST.
* The (sadly unfinished) ''Film/{{Ghostbusters}} Doom'' GameMod for VideoGame/{{Doom}}, which recreates scenes from the movie, fulfills this trope with its first level - the haunted library. While the original film scene was quite amusing, its recreation in the mod is much [[http://www.youtube.com/watch?v=h3_oat_4plA creepier.]]
** And then three levels later, you have to investigate a haunted mansion, in the rain, with creepy music, and corpses everywhere, and the corpses start standing back up. They take way too much punishment just to shoot off one of their arms -- you have to deal just as much damage a second time to get one to stay dead.
* Eternal's Epic2 wad is a collection of egyptian themed levels, city levels and spaceship levels. One of the spaceship levels, level 13, takes place in this very eerie, dark, grey and white spaceship made of what seems to be rotting tissue. The soundtrack for this level is definitely creepy, very different from the others. The battles are exclusively with arch-viles (arguably the creepiest enemies in vanilla Doom), most of them used through teleport-traps. Health pickups? Aside from a secret soulsphere, the only health pickups are accessed through computer panels marked with a scarab, restoring 20 health each.
* ''Pirate Doom'' has mask-wearing island natives. They're very weak enemies, but because they're small, fast, numerous, and relatively quiet, you'll often turn around and have one right in your face. They're also animated to giggle before shooting at you, so you'll also turn around to see one right behind you, just standing there giggling. It's creepy.