You know those moments, the ones where a major enemy pops up out of nowhere, or a cutscene hurls you into the deepest level of hell with no indication of what you're supposed to do. We've all had at least one of them, with all of the games that tend to confuse true horror with startling the player until they're deaf, dumb, and blind. So let's hear them! What's your biggest "Oh Sh*t" moment in gaming?

Personally, mine came when I was playing World of Warcrack(I know, I'm an addict, so sue me.) It was only a few days ago when my Alliance friends and I planned a raid on Thunder Bluff, only to discover a few moments too late that the biggest Horde PvP guild happened to be having their monthly meeting right in front of the big boss. Needless to say, it was a bloody massacre.

I've had plenty of those. CoD4's Nuclear blast being one of them. Giant beasties scare me sometimes too. the first time I saw a Brumak on Gears of War, and also the first time i stepped into the dark in the night level. Damned kryll. Devil May Cry 4's massive statue was painful too :/

Quake Team Fortress. The first time I saw a scout double concussion grenade themselves up the elevator shaft, with my flag.

[EDIT: on 2fort4, obviously]

I immediately committed suicide out of respect for the total awesomeness that was my enemy.

Not too long ago, but in WAR I was doing a public quest for the first time, in a relatively small party. The current stage was nearly finished, and just as the final crystal or whatever was clicked, big lightning bolts started dancing around and low and behold... a lord of change (or Greater Daemon of Tzeench to those lesser warhammer inclined people, and A giant fucking bird/man monster to those even less so) Now, it just happened to spawn right behind me and had people on teamspeak shouting "behind you!"

Que turning around slowly, just in time to see it one-shot my bright wizard. But not without enough time for me to go oh $#%&!!! first :D

Call of Cthulhu: Dark Corners of the Earth. When doing the first prolonged run away sequence (Y'know the one, after the hotel) I had managed to sneak around in the warehouse. Then I got out and I heard a shot. I just booked it. Screw sneaking, I just ran as fast as I could muttering "Oh shit, oh shit, oh shit, oh shit!"

I was exploring somewhere in Fallout 3, when I fell down a hole to be surrounded my a mix of Talon mercs with missile launchers and super mutant brutes. They seemed to stop fighting each other when I showed up.
You can see boss battles coming, so they don't really do that to me.

The kryll in Gears of War was a big one for me. They killed me 2 times before I figured out what had happened. I probably should have been paying more attention.

Hm, I think my biggest oh *#%@ memory in recent times was playing multiplayer in the L4D demo. We were passing by a witch and I'm all like, "Don't stare at it too long, don't shine your flashlight, don't shoot."

-One Moment Later-

You have startled the witch.

Me: "Wait what??? What did I do??? Someone save me!"

The newest one for me was when I beat Resistance 2. I won't give away any spoilers, but damn what a great ending!

Brokkr:
The kryll in Gears of War was a big one for me. They killed me 2 times before I figured out what had happened. I probably should have been paying more attention.

The kryll are awesome if you're watching or playing co-op for someone who isnt a gears player. They go WTF or oh sh!

Almost all of L4D.

Left 4 Dead has given me more 'OH S&#@!" moments than I can even count. The most memorable was the third time I completed the No Mercy campaign. At the end you climb a ladder out onto the roof of a hospital. For a time, you're elevated off the main rooftop and (the first two times I played it) there were numerous zombies sprawled out below us just ambling around. In my first two playthroughs I had been armed with the sniper rifle and thoroughly enjoyed the momentary turkey shoot that ensued.

Well, I was playing with some friends who hadn't beaten No Mercy yet, and therefore had no idea what to expect and my friend Rob had the sniper rifle.

So naturally, over my Xbox LIVE headset, I said, "Hey Rob, this section is going to be fun for you."

My shotgun and I were the first up the ladder and I looked out on the rooftop and didn't see a single zombie.

Just as my teammates cleared the ladder, a flood of zombies came pouring up it behind us. Needless to say, "OH SH*&!!" were the only words I could muster.

After we managed to frantically clear them, my buddy Rob said, "Dude, that wasn't any fun at all."

TheGhostOfSin:
Almost all of L4D.

I had heard that from a friend who owns the game, but I don't, so I wouldn't know.
Being a college student under massive amounts of debt, I don't have the cash nor the time to play new games.
I anticipate a lot of answers coming out of L4D, but it's all good, let's hear them anyway!

TheGhostOfSin:
Almost all of L4D.

Amen. Just amen. You are hereby heralded as the prophet of truth.

Now....TANK!!!1111oneone! >: O

The first time the car alarm went off in Left 4 Dead and the zombie hordes start pouring out from everywhere towards you like a big smelly tide of death. That was a good one.

My biggest oh $#!+ moment was in Doom2, in one of the random .wad addons I had there was this one level with a bunch of signs pointing to a room and when you get to the room theres all kinds of goodies. Well when you walk into the room you fall down and 7 Cyberdemons happen to be down there with you, needless to say it was one of those random oh $#!+ moments for anyone who wasn't expecting it. I was like 6 at the time so theres no way I could have expected something like that, but since then I always expect that anything can and most likely will happen and am always ready for 7 Cyberdemons to pop out of nowhere.

I'd say mine would be Dead Rising. I had heard about the psychopaths and the cult members, but it wasn't until my first meeting with the clown that I thought... OH SHIT! And the cult members would always run at me when my back was turned...

Star wars galaxies. I had quite a strong character and me and 2 buddies were running around as rebels in correlia. We decide to go have a look in the spaceport to hope and find some imperials. We run in and suddenly we see 30+ imperial players with 3 AT-ST's.

That was my OH SHIT ON A STICK moment...

Biggest OH Sh!t moment in videogaming? My ps1 memory card committed suicide towards the very end of Xenogears....had to start over....never got that far again.

edit: I realize this particular instance doesn't quite fit in with the criteria mentioned in OP. So to correct that:

Diablo 1, level 2: made the mistake of opening to the door to the room covered from top to bottom in people pieces. "Ah, FRESH MEAT!" ::shudder:: never again....

Every time I saw a colossus in Shadow of the Colossus. Probably one of the best gaming experiences ever.

*Runs off to un-dust PS2*

fish food carl:
This thread has been done before, pretty recently in fact. I advise that you use the search tool in future.

I thought the nature of the first one was different to this one

Duriel. That is all.

When i was surrounded by Corsair Titans in a radioactive cloud in Freelancer. I just looked on my radar (or whatever it's called) and said "Oh @!#^".

Oh @!#^ -RELOADING- a tank.

Fallout 3 In tenpenny tower where ghouls invade and there are lots of them, but you get a special mask that makes them not attack you. Now i was looting the guest whom had just died and in my inventory i saw an unequipped power helmet and i though "why aren't i wearing my power armour? Best put it on so i don't die" Mauled by fifty fucking zombies before i could raise my shotgun i had my weapon hit out my hands then mt arm ripped off then my head ripped off.

That was my biggest "oh shit" moment ever.

The very first flood level in Halo: Combat Evolved. Oh my, I was scared as hell.

Ice Storm:
The very first flood level in Halo: Combat Evolved. Oh my, I was scared as hell.

Not to mention that's it's almost bloody impossible to complete. If I had a nickel for every time I died in that level, I'd have enough cash to buy fifty more copies of the game.

3 Tanks popped up at the same freaking time in Left 4 Dead on Dead Harvest. We got one guy to the getaway vehicle, and even he got killed from a damn rock that the one outside threw. I was pretty damn pissed when we got to the end and then those f#%kers came and killed us simutaniously. I think the AI Director has it out for me! =)

The giant robot you have to run from in RE:5

In Guild Wars: Nightfall, there's a quest where you escort this librarian into a hidden city to find 'the Gift of the Djinn' or something like that. You have to beat two bosses (I got stuck on the second one, as he was in the middle of a four-way intersection surrounded by fire-nukers and these REALLY annoying lion things that can resurrect each other). After I beat the second boss and put the essences or whatever on the pedestal...

Oh, and any time in the Fissure of Woe when that idiotic Rastigan the Eternal plunges into the mob on the OPPOSITE SIDE OF THE FIELD of the mob I had been clearing for him, and gets killed.
...HOW DOES AN ETERNAL THING GET KILLED?

fullmetalangel:
Hm, I think my biggest oh *#%@ memory in recent times was playing multiplayer in the L4D demo. We were passing by a witch and I'm all like, "Don't stare at it too long, don't shine your flashlight, don't shoot."

-One Moment Later-

You have startled the witch.

Me: "Wait what??? What did I do??? Someone save me!"

Ahaha that happens to my friend all the time. Once I actually shot the witch by accident and the game still said that my friend startled the witch. I just told him its his attractive personality, women just can't stay away from him, alive or dead.

Hmmmm really haven't had a "Oh $#!+" moment in a while. Well I guess I kind of did when I was standing in a puddle in R2 and one of those furry things came up and bit me in the ass.

fish food carl:

kapzer:

fish food carl:
This thread has been done before, pretty recently in fact. I advise that you use the search tool in future.

I thought the nature of the first one was different to this one

No, not really. Surprising moments? Check in both. Scary moments? Check. Forboding moments? Check. Nope, this is the same thread. Sorry.

I dunno...
A lot of moments can be surprising or scary or forboding...
But there's only certain moments, the really, really bad ones...
That just make your eyes pop, your jaw drop, and your vocal cords reverberate with the ever-so-popular, "Oh... Shit..."