Sometime's this game can freak me out.Like this one time I was in a shootout with some bandits.As soon as I killed all of them.Out of nowhere this creature smacks the shit out of me from behind and killed me.At first I was like wtf,because I didn't know what the creature was at the time.Later on I found out it was called a deathclaw.I had some other moments like the time I was in a cave.Searching for supply's and stuff I could use.But then I heard noises coming from behind me.I turned around and a barrage of mutated flies attacked me.They killed me before I had time to react. 
 
But anyway have anyone of you guys had any scary moments while playing new vegas?

I once saw a Giant Ant that was glitched into the ground and was freaking out and twitching. Pretty frightening for the first 1000 times, but then it just gets old.

I heard a woman get raped just outside of New Vegas.  I tried to find where she was and help but I couldn't find her.  Then the screaming stopped.  That was pretty messed up.

" I once saw a Giant Ant that was glitched into the ground and was freaking out and twitching. Pretty frightening for the first 1000 times, but then it just gets old. "

I had a glitch where scorpions was flying in the air,and the ground was turning blue.It was very weird and creepy.

the worst moment for me was the time i was running through scorpion gulch, or some shit like that while making my way to hidden valley. i killed two giant radscorpions and then got mauled by a horde of them as well as some bark scorpions. i really hate scorpions. i have a real life fear of them ever since having an encounter with an albino emperor scorpion when i was 4 years old. I HATE THOSE FUCKING THINGS!

Early on in the game I ventured into Camp Searchlight and was attacked by 10+ ghouls. That was some creepy shit.

Nightkin. 
 
Fuck those guys.

Sneaking through a completely unseen shotgun-tripwire trap.

All the glitches really are frightening.
 
That's not even a snide comment. There's a train tunnel (in an area surrounding by Deathclaws) where if you attempt to walk up the steps you will fall right through the ground and it made me jump.

I feel like the classic glitch of corpses/skeletons having seizures in midair (a glitch that even occurred in FO3) is still the most frightening thing I've ever seen out of this game. So freaky! 

There's nothing more frightening in Fallout than having the music ratchet up and turn around frantically, only to see nothing. I'd always start tapping RB instinctively whenever I hear that enemy music, because god damn it Deathclaws scare the fuck out of me when they creep up on me.

There was this one giant radscorpion  that basically followed me through the entire game, like some sort of fucked up, twisted version of Mordred from Dark Tower or something. I think it was dead, but it was hard to tell because it's body was twisted up in a ball, twitching wildly and occasionally flying through the air and/or popping up through the ground. It alternated between being hilarious and very unsettling and would appear and disappear at random, vanishing for hours before reappearing again across the map.

A couple times in New Vegas and FO:3. I remember I was in the vault with the mutated plants and preying mantis and I was just walking around and bam! Preying mantis jumped in front of my screen out of nowhere! I just screamed, fell to the floor and laughed because it scared me shitless. Another part was I was going to New Vegas for the first time and I had Boone and Ed-E on my team. Saw 2 deathclaws running towards me and we killed them. 2 seconds later and literally, at least 6 or 7 deathclaws were running towards us. I just left Boone and Ed-E to fight, turn around and 2 deathclaws smacked me. Dead. That was stupid. In FO:3, I always got scared by mole rats attacking me because I didn't hear them chasing me.

I downloaded the new patch before I knew it was screwed up. Now I'm scared to turn on the game.

Scary moments in New Vegas all came out of either glitches or the possibility of glitches for myself.

Dark basements + Nightkin with stealth boys = horrible surprises

Deathclaws, they come out of nowhere and from behind you, in which case i either turn around just before the attack and have a heart attack, or i see that half of my hitpoints just went down...in which case i still know its a deathclaw behind me.

Not in NV yet but in Fallout 3 the hospital was pretty scary.

Especially at night

yep, forgetting to save for hours without going through any doors and loosing hours of grinding enemies in the wasteland when the game freezes.

I'm deathly afraid of ghouls, and their sound effects are so awful (and amazing), so whenever I meet them or hear them in a dark building  I shit my pants. Alslo the coyote-snake-invisble things are very damn freaky. Vault 34 or wherever it is with the, um, green guys, is very jumpy and creepy. Really well made that place.

  

  Does this count?

Nightkin and Ghouls they always freak me out.

Vault 22.

Fucking Cazadores came out of nowhere.

Sneaking through deathclaw land with a couple of stealth boys to get the tesla armor.

In the Camp Searchlight fire station, when i came into the garage. A giant radscorpion queen just appeared from nowhere and killed me.

The first time I came across a Nightkin. The fuckers uncloaked and started attacking me out of nowhere. Also everytime and enemy would get stuck in the ground and start stretching out to free themselvs.

Vault 22.

  

  Does this count?

I know what you guys mean about those nightskin. The first time I saw them they appeared in front of me. I didn't see them at first because they had cloak. My heart just started racing because it caught me off guard. Sometimes playing this game felt like a survival horror.

@Delicious_Brains said:

Sneaking through a completely unseen shotgun-tripwire trap.

Piss on the goddamn rug.;

Other than fearing of corrupted saves, New Vegas is waaaaaaaaaaaaayyyyyyyyyyyyyyyyy less scary than Fallout 3. Everything other than the towns in FO3 are creepy as shit.

Only scary moments in this tend to be running into a bunch of the deathclaws when not expecting them or when the game locks up.

I wandered around the Quarry when I was level 10 or so and was ripped to shreds by a deathclaw alpha.

I have the Wild Wasteland perk you get in the very beginning of the game, but the only thing that has happened was that the fallout boy in the in the corner is dizzy which symbolizes an emotion or feeling and I get this weird light flash thing like after you finish a drug or something. I was hoping to see skeletons and such pop out of the ground and drag you through the Wasteland but I guess not. I hate walking into a house with scorpions in them, and it's a little house too so you're trapped unless you turn around fast enough not to get stung. 
 
The video was flipping scary, and what made it worse was my TV turned off right mysteriously (as it has no remote) as the scary part happened. 

The Vaults are pretty creepy. Also, Nightkin have straight up scared the shit out of me on more than one occasion. 
 
Especially in the REPCONN test site basement. God damnit, that was bad. 

Fallout can be pretty scary, man. People complain about not having a run button, yet I find myself spending the majority of the game crouching in fear...

LOL!

Vault 22.

Nightkin, BY FAR!

Once I got the Anti-Material Rifle i didnt hate Deathclaws TOO much, but when there are like 5-6 of them you re just raped.

But Nightkin FUCK THOSE GUYS! When I got the REPCONN mission in Novac, I just went around it, FUCK THEM!

I just tend to stay away from any and all vaults. Those tend to be the scariest especially when you start piecing the story of whatever terrible thing was done to its inhabitants. Though some of those stories are fantastically scary and make for decent short-form horror on their own.

The mission where you're in the RepConn factory (main quest, on the way to New Vegas) was scary from start to finish. I just hated walking around that dark building, not knowing exactly when a feral ghoul would jump out from around the corner. I was on my toes the entire time I was doing this quest. It didn't help that I was playing it late at night in a room by myself either.

Basically anytime I had to go underground pissed me off, but the nightskin? nightkin? Invisible guys were not only a bitch at an early level but kinda scary.