Even Bugs Bunny had a couple of moments like this; once in a Mad Scientist Laboratory when he sees the Hyde-like monster behind him, and again when he accidentally takes off in a rocket and looks down to see the Earth falling away below him...
Chuck Jones is clearly the undisputed master of the cartoon Oh Crap face.
You know Bugs is in serious trouble when his eyes widen and ears fall.
In a lot of cartoons with Yosemite Sam, he thinks he has gotten the better of Bugs, only to realize he's in trouble, and goes from an Evil Gloating to and Evil Laugh and then to an Oh Crap rather quickly. For example, in "Hare Lift" when he parachutes out of the plane with his stolen money:
When the Hun army appears on the snowy ridge, everyone in Mulan's squad clearly recognizes that they have no chance of getting out of the coming battle alive.
The DCAU is fond of the "Oh, no" variant, and manages to keep it consistently funny, at that. The greatest example possibly comes in Justice League Unlimited, when the time-traveling villain Chronos sends one of the Jokerz back to the time of the dinosaurs for betraying him:
Kalibak: I just flattened Wonder Woman! You really think you can beat me? Batman:I'm not trying to beat you. I'm trying to stall you. Kalibak: Stall me? For what? (turns to see Superman behind him) Aw— (punched in the face)
At the very end of "Secret Society", we are treated to a gorilla's Oh Crap face after Grodd attempts to use his psychic attack on Superman, who manages to resist enough to flick Grodd in the nose, sending him flying. A little earlier, Shade had one on as Superman, in the blink of an eye, interposed between his fist and Batman.
There's a pretty priceless one early on when Lex Luthor is informed that while humans are mostly unaffected by Kryptonite, studies have shown that it can cause blood poisoning in terrestrial life if the subject is exposed for a long period of time. Lex happens to carry some around in his pocket.
Luthor tops himself in the episode "Alive!", part 1 of the series finale. His change of expression from exultant triumph to shock and horror when he resurrects Darkseid instead of Brainiac is just epic.
At the end of the episode "This Little Piggy", when Zatanna is magically tossing things at Circe:
Circe: Insolent trickster! You dare to strike... (smacked with a table) You dare to strike... (smacked with a chair)You dare to strike...(covered in a tablecloth, yanks it off) QUIT IT! Oh, no...(hit by a piano)
A brief one from the first part of the above-mentioned Chronos episode: Green Lantern and Batman are sitting in the cafeteria discussing their respective love lives; Batman is explaining that Wonder Woman is not his girlfriend.
Batman: She's a good friend, a trusted colleague. She's...
From the JLU episode Grudge Match. Hawkgirl, Vixen, Black Canary and Huntress, four of the toughest women in the League, have just shrugged off the mind control forcing them to fight each other. They stand ready to face the villain...who brings out a mind-controlled Wonder Woman. Four to one odds and they're still in big trouble.
This one takes most of the episode "Far From Home" to set up. Supergirl, Green Arrow, and Green Lantern are abducted to the 31th Century by Brainiac 5, who is nearly clobbered by Supergirl before he can explain that he's a good guy, unlike that OTHER Brainiac. The two eventually hit it off.
In the last scene, GA and GL are back in the present, and show Superman a farewell video from Supergirl: she's staying in the future because it's more like her lost home, and "Also, I met this guy...." It's a heartwarming moment as Superman realizes that although this is the best for her, he may never see his young cousin again.
Then, smirking a little, he turns to the heroes:
Superman: So this boy she likes — does he have a name?
In "The Laughing Fish": The Joker jumps into the ocean, completely forgetting about the shark that had recently been released
Joker: See, Batsy, I think of everything! Hahahahahahaha— AAAAAAAAAAAAHHHHHH!
"Almost Got 'im":
Several villains have been sitting around playing poker and sharing stories about how they almost killed Batman, but failed. The Joker's story ends with him successfully capturing Catwoman and he reveals her location, and that he's about to head off and finish her. Then Killer Croc says "I don't think so" in Batman's voice, and the Joker's expression in the split second before he's thrown across the room is priceless.
Harley Quinn gets one in the same episode; guarding the Death Trap that Catwoman has been placed into when Batman comes calling, when Batman captures her Harley smugly gloats that he can either beat her up or save Catwoman, and can't do both. Unfortunately for her, she's neglected to consider the large circuit breaker the two are standing beside, and when he just shuts the power off her expression and reaction is even more priceless:
Harley:(Weakly) Heh, heh... good call. Help!
Regular Gothamite Charlie Collins is driving home after a miserable day at work when some jerk cuts him off on the freeway. Charlie pulls alongside the other driver, rolls down his window, and proceeds to cuss and threaten the other driver... until said driver turns and gives him a BIGGGG smile. Charlie's face is pretty much distilled Oh Crap at that point.
Charlie returns the favor by trapping the Joker in an alley with a bomb. Joker is absolutely terrified, thinking he's actually going to die, and cries out for Batman to save him. Batman is actually about twenty feet away, watching the whole thing, and Charlie knows it. But Batman lets the Joker sweat for a few minutes before stepping it.
"Fear of Victory," when a bookie's henchman is sent to find out why "Mr. Lucky" never loses, no matter how many bets he places. The henchman follows Lucky to an abandoned horse stall, threatens him, and goes to pull him out of the shadows... only to find out he has just collared the Scarecrow. Things go downhill from there.
And of course there's also "Two-Face, Part 1," when Big Bad Harv takes control over Harvey Dent:
Harvey: There's just one problem.
Rupert Thorne: What?
Harvey: You're talking to the wrong Harvey.
The scene from the episode of Static Shock where the Joker shows up to cause trouble in Static's neck of the woods. At the end he's been defeated and tries his famous joybuzzer trick on Batman, but Static grabs his hand instead. I love the Oh Crap look he gets when not only was his joybuzzer ineffective, but Static decides to return the favor in his own way. The Joker was very shocked by that turn of events.
"Solar Power", this is essentially Luminus' expression when he realizes that the depowered Superman is returning to normal.
"Superman's Pal" gave Metallo a brief one when he realized that Jimmy had just removed his Kryptonite power source. He has time for a brief shriek before he collapses.
In Legion of Super-Heroes, when Imperiex realises that by turning the sun yellow, Brainic 5 effectively turns the whole population of Kandor into Supermen.
Imperiex:I suggest we worry about unshrinking ourselves WHEN THERE ISN'T AN ARMY OF SUPERMEN BEARING DOWN ON US!
That Dark Circle guy's face when he pushes the trigger for a bomb supposed to blow up a satellite but it fails to go off is classic.
Dr. Londo's pretty good at pulling these, first was when his mutated creatures turn on him and the second time has his clone display an even more accurate depiction of this trope when his attempt of reasoning with his berserk son fails who subsequently kills him
Both main characters of Invader Zim have been on the receiving end on this trope on several occasions, the most obvious example being when Dib sees the massive water balloon about to crush the city (and him) in "The Wettening". Even secondary characters aren't immune, with the Tallests (along with their entire crew) displaying classic Oh Crap expressions as their ship, being controlled by Zim, is about to crash into a sun.
Ozai gets a somewhat more subdued Oh Crap expression earlier in the same fight, when Aang catches his massive Comet-enhanced lightning attack and looks like he's going to redirect it right at Ozai, who unlike Aang had no way to defend against lightning. But since Aang refused to kill, he redirected the lightning into the sky instead.
Jet gets a slow-motion zoom-in shot of this nature when Long Feng kills him.
This is Aang's reaction when he just barely manages to save himself from getting skewered with a throwing star in his first battle with Mai.
Sokka also gets several, one notable example of which is his expression in Episode 2, when the Fire Nation boat is about to mow him down.
The look on Zuko's face when he realizes that his sister is about to wipe the floor with him at the start of Book 2 really says it all.
Also in the Book 1 episode The Storm. During a flashback, younger Zuko does this when he realizes that his own father is about to burn the royal crap out of him.
Actually, Zuko gets a lot of these... practically once an episode during Book 1.
One particularly epic one came in chapter 18 when Zhao sees and recognizes the swords used by the Blue Spirit (Zuko) when he freed Aang from the Fire Nation fortress. Zuko instantly realizes that Zhao just put two and two together and the look on his face just screams this trope.
In the Day Of Black Sun, we get a close-up of Aang's face panning out◊ to reveal an equally shocked Sokka.
The characters and viewers get one towards the end of that two-parter with the reveal not only that the Mechanist's air balloon had been mass-produced by the Fire Nation, but that they'd gone and invented airships.
Zhao when Tui grabs him. That is all.
A little bit before then, Zhao realizes he's in deep shit when he kills La, and Iroh retaliates.
Azula herself gets one in the Grand Finale... when Katara encases her in a block of ice
Katara gets one of these towards the end of Season 2, when she discovers Zuko in Ba Sing Se, goes to the palace to report him, and there runs into Azula and company disguised as the Kyoshi Warriors. Not your lucky day, Katara.
After taking down a bunch of Fire Navy ships at the North Pole, Aang looks out a bit farther to sea and realizes he still has a few hundred left to go...
Crowning one goes to the opening of season 2, where Azula and her elite guard almost tricked Zuko and Iroh onto the Fire Nation boat. When the captain uttered "we're taking the prisoners home", not only does he get an Oh Crap face, but so does Azula, Iroh and Zuko. 4 for the price of 1!
Iroh doesn't really give an Oh Crap face as he suspected this kind of treachery. His face was more of a "Time to kick ass" face.
And Azula's wasn't really an Oh Crap face either. It was more of a "you idiot!" face, as she was looking directly at the captain.
The Earthbender general in "The Avatar State" gets one when he realizes that Aang in the Avatar State is not too happy with him.
One more for Azula (as the show's resident Magnificent Bastard, she doesn't get too many herself), during the season two finale when Aang collapses the rock formation she's clinging to. Particularly notable as the only time we ever hear her gasp in fear.
Hama gets two moments in The Puppetmaster; once when Katara breaks free from her control, and again just before Katara floors her with a powerful waterbending attack.
From the first season, the episode that introduces Hei Bai has two, both involving Roku's dragon. The first, of course, is when Aang sees the dragon heading towards him, and realizes that he can't bend in the Spirit World, and the second is when the dragon banks up and flies towards the ceiling in Roku's temple. Seeing that the dragon never did intend to hurt him, though, each of these instances would probably count more as a subversion.
When the sandbenders steal Appa and Aang finds out, it's too late for them to do anything about it. Aang gets Glowing Eyes of Doom, and the sandbenders realize that they are facing a Physical God who is insanely ticked. Sure, Aang cools down before any real damage is done...but even Sokka and Toph were running away scared.
Oh man, when Avatar Roku manifests before the traitorous fire Temple Sages, he ain't happy about the way they've been treating his reincarnated self. The poor sages don't even stop to think, no - they just shit their pants and RUN.
In the second episode, Korra participates in a pro-bending tournament. Tenzin hears about this, and comes to retrieve her. Korra gets knocked off the platform during the tournament, and as she swims to the edge, Tenzin is standing not five feet from where she pulls herself up. She tries brushing it off casually, with only slight amounts of success.
In "When Extremes Meet", this is Korra's priceless reaction to Ikki revealing to Asami, Mako's girlfriend, that Korra loves Mako
In the same episode, Korra gives one when she realizes Tarrlok can bloodbend and in the next episode Tarrlok gets one when Amon resists his bloodbending.
In the season finale, Amon when Korra finally starts airbending and when it's revealed to his followers that he's a waterbender and bloodbender. These are the only two times in the series where his unflappable demeanor goes away. It's also the only time in the series where he has no plan to fix it.
Pema pulls one heck of an Oh Crap face when Asami and Mako start to argue.
The look of pure abject horror on Optimus Prime's face when the restored Megatron (whom he'd thought dead since the first episode) bursts out of Sumdac Tower is priceless. This is a 'bot who understands exactly how completely and utterly screwed he is.
The Elite Guard get a big one when, after insisting for the entire episode that there are no Decepticons on Earth, they face off with Starscream, who is more than willing to show the lot of them a taste of what Optimus has been up against.
Ultra Magnus has a pretty good one. After telling the Autobots to stand back, he presumably intended to deal with the situation. As soon as he turns around, Starscream has recovered and is pointing his weapons right in Magnus's face. *blast!*
Also from the 80s movie. Galvatron's expression when Unicron begins to transform is about the purest expression of this trope as I've ever seen.
When Optimus Prime arrives on Earth to save the beleaguered Autobot City, he goes on a Foe-Tossing Charge in his vehicle mode. Thrust is his first victim, and we're treated to the sight of Thrust's eyes going wide in horror as Optimus barrels at him...reflected in Prime's grill. Cue Thrust being flung through the air.
Happened to Butt-head in Beavis And Butthead's Butt-O-Ween special. But, being Butt-head, his facial expression remains static, and his reaction amounts to "Uhh, uh-oh."
Done often in Total Drama Island. For example, when Owen has to get a key from a sleeping bear:
Owen: Oh crap oh crap oh crap! (the bear puts Owen's head in its mouth, still sleeping) Owen:(whispering) Oh crap... (the bear wakes up) Crap infinity...
Also done whenever the season's Magnificent Bastard thinks that he/she is about to be voted off.
Drakken also has an "Oh, crap!" moment when he realizes Shego must also be wearing a Moodulator like Kim, which he just locked into "an irreversible frenzy of rage":
Inventor: If she's wearing Moodulator #1, then where is the second one? Drakken: The second one?... Uh-oh...
And Ron had one shortly before, after the inventor informed him that Kim was now locked in an "irreversible frenzy of rage...so I hope she's not mad at anyone." Ron had just given her the 'let's just be friends' talk.
When gloating about having defeated Kim, Drakken looks up◊ from his knees to see... one very pissed off Kim◊. So scared is he that he only reacts after she punches him across the room.
And Kim's not invulnerable either. She has this reaction upon meeting Oliver, the 7 foot tall by 4 foot broad boyfriend of Vivian.
Both and Kim and Shego (who was good due to the attitudinator) had this reaction when Ron was turned evil again.
Kim: Not again.
Hego: What's wrong with him?
Shego: I think he's evil now.
Hego: How bad could that be?
Shego: You'd be surprised.
Buck Strickland's immediate reaction in King of the Hill to Peggy bursting into the bar he's holed up in after driving Hank to embarrass himself out of a job.
Of course, it turns out he was right but it still counts.
Darkwing Duck: This reaction usually followed the mighty midnight mallard's confident heroic banter right before he got pummeled. It never lasts long; in mere seconds, he's back to scheming and scrambling for the means to thwart evil.
In The Simpsons, where Krusty gets arrested for tax evasion, we see one side of a telephone conversation with his banker in the Cayman Islands.
Banker: Sorry, I'm not allowed to divulge information about that customer's secret illegal account. (hangs up) ... Oh Crap, I shouldn't have said it was a customer. Oh Crap! I shouldn't have said it was a secret. Oh Crap! I certainly shouldn't have said it was illegal!... Oh, it's too hot today.
In a "Treehouse of Horror" spoof of the Omega Man, Comic Book Guy does this as a nuclear missile hits him dead on in the face.
Comic Book Guy: But Aquaman, you can't marry a woman without gills! You're from two different worlds! (looks up and sees missile) ... Oh, I've wasted my life.
Troy McClure gets a literal "Oh Crap" moment when, during an infomercial for Dr. Nick's Juice Loosener, he tries on Dr Nick's Tanning Cream/Laxative.
Bart Simpson has one of these moments after he burns his name into forty-foot long letters on Springfield Elementary School's athletic field with grass killer. An enraged Principal Skinner roars Bart's name after seeing it, and Bart gulps both audibly and nervously. He then has another moment when Skinner is yelling at him in his office:
Skinner: Surely you realized that by writing your own name in forty-foot letters that you would be be caught.
Bart: Maybe it was one of the other Barts, sir.
Skinner: THERE ARE NO OTHER BARTS!!!
Bart: Uh oh.
Near the end of "Marge vs. The Monorail", Smug Snake Lyle Lanly loses his smug expression and freaks out when he realizes that his plane to Tahiti is making a stop at North Haverbrook, the last town he ruined with his monorail scam. His panic is justified — moments after the plane lands, an angry mob of North Haberbrook's remaining inhabitants attacks it.
In "Marge in Chains", Otto sunbathing on a rooftop, just as he realizes he's about to be hit by a dollop of vomit infected with the dreaded Osaka Flu falling from Arnie Pie's helicopter. Shown from the perspective of said dollop.
"And now a word from our new sponsor...PERCODAN?!? AW CRAP!"
Nelson in "22 Short Films About Springfield", when he realizes that the Very Tall Man has stopped his car and is coming after him for laughing about his appearance. (Then again, after Lisa tells the guy that Nelson is hiding down the manhole.)
In the Winx Club season 2 finale, all good guys present in Realix had this reaction when Bloom ignored Sky and continued to give Darkar the Ultimate Power.
Megabyte from ReBoot is not only a stoic and sophisticated Chessmaster and master manipulator, but also the most physically-powerful program in Mainframe. His memories of Enzo Matrix are of a brash, overconfident, hyperactive little boy. So when the now grown up Future Badass calling himself Matrix falls for his goading, tries to beat him up personally, lands one, and leaves a fist-sized dent in his chest... it's one of the best facial expressions in the series.
Later that same episode, after Matrix defeats him, and refuses to kill him, Megabyte prepares to escape Mainframe anyway by using a portal to the Supercomputer. Then Mouse hacks the portal to send him to the Web, instead. His reaction when his last gambit fails says it all.
Played for raucous laughs in an episode of Rocko's Modern Life. One of his new jobs in a long string of job hunting results is him working at what is for all intents and purposes a phone sex setup (this series got a lot under the radar). Of course, when he and the person on the other line recognize one another's voices...
Rocko:(monotonic, unenthusiastic) Oh baby, oh baby, oh baby... Mrs. Bighead: ... Rocko? Rocko: ... Mrs. Bighead?! (both slam the receivers down on their respective phones)
The Earthworm Jim cartoon gave many of these moments to its villains, particularly to Psycrow, as in: "...You're gonna hit me really hard now, aren'cha?" But special mention has to go to the Oh Crap moment they work in to a musical number.
Used my Mr. Krabs in an episode of Spongebob Squarepants, when Spongebob tries to free captive Jellyfish from him
Spongebob: And now I'm going to set these jellyfish free! (attempts to open the door) Mr. Krabs: *laughs* Well, you can't. The door's voice activated, and it will only open if I say "Open". (short beat, then he suddenly realizes that he just said it)
It's a blink-and-you'll-miss-it, but Slade of Teen Titans got a really good one in the episode "The Prophecy". Particularly sweet, because up until that point, Slade had been the stoic,quiet, chessmaster villain. Then Raven shows up and gives him a good old-fashioned ass kicking.
Of course, Slade himself tends to generate these moments too, especially during Season 4 when he comes back from the dead as The Dragon of Trigon. The Titans got a collectiveOh Crap look when they first saw him.
Slade also gets a very quick one in "Betrayal" after he shoots Beast Boy. When he looks up after briefly taunting Terra, he briefly goes (one-) wide-eyed to find himself facing one very ticked off giant green bear.
Doctor Light gets a classic one. After gloating and preparing to make his getaway, Raven shows up behind him, in full scare the crap out of you mode, with that immortal line "Remember me?" Light's face goes white, and he calmly asks to go to jail.
One of the biggest ones is when Leonardo is sent crashing through the window of April's apartment, nearly dead. In rage, Raphael is about to leave to find out who was responsible and make them pay, when Leonardo struggles to talk and stops him from leaving. His last words before losing consciousness??
Terrorsaur: Blast those Maximals! They destroyed my power! But at least I got rid of Megatron. Megatron: Well, well, look... who's... back! Terrorsaur:(tiny voice) Help!
In "Other Voices Part 1", Optimus Primal has been captured by the Vok and scanned (which is incredibly painful). After recovering somewhat, Optimus opens his eyes... and nearly shits himself when he sees the head of Unicron staring down at him. He calms down when the Vok explain that they looked into his memories and are using A Form You Are Comfortable With.
Metalocalypse, "DethHealth": Nathan Explosion gets one of these in this episode. The usual mayhem goes down at a Dethklok show, with much of the debris nearly missing crushing the band:
Nathan Explosion:(with requisite expression) Oh shi— we nearly died!
The guys' reactions when Offdensen angrily confronts them about booking a gig in Syria definitely qualifies. Considering that it's the closest Offdensen has ever gotten to completely losing his composure, even some of the fans had Oh Crap reactions to it.
In Futurama, one of Bender's more common expressions is "I'm/We're boned!", for more or less these kinds of situations. He gets himself into trouble a lot. Another Catch Phrase of his is "Cheese it!", also for these kinds of situations.
The characters of Ed, Edd n Eddy got three in quick succession in the last ten minutes of the Grand FinaleMovie: Eddy, when his brother demanded that he "play Uncle", Double D when Eddy's brother starts beating the shit out of Eddy, and everyone else when Eddy's brother starts to beat up Double D using Eddy as a club.
Eddy's Brother when he sees a steel door rocketing straight toward him.
Dr. Venture of The Venture Bros. pretty much whenever he screws up or pisses someone off.
Another good one was in "Aces and Apes." The Rangers are chasing Lazarus Slade, who is a marginally competent member of their Rogues Gallery...but then they see that Slade has a partner. Said partner is The Scarecrow, arguably their nastiest opponent.
On Drawn Together, Xainder has these a lot, more often than not due to Captain Hero.
D-list bad guy the Mandrill gets a great example of this during the beginning of episode 3 of The Avengers: Earth's Mightiest Heroes. After robbing a bank he is confronted by...the Wasp. He's less than impressed. Then Iron Man shows up. Still confident. Then Thor, Giant-Man, and the Hulk show up. His spectacular oh crap face is followed by a wise choice to surrender.
Another great example comes when the Avengers must stop Kang from taking over New York. When Hawkeye and Hulk encounter some of Kang's robots on a bridge, Hawkeye tells the Hulk to go rest while he fights them solo. The robots then combine into one Giant Mecha, leaving Hawkeye shocked.
Five Avengers react like this after Ultron's beam apparently causes Thor to vanish.
And in an earlier one, Scrap-Iron gets an awesome one in slow-motion when a mech-suit equipped, Unstoppable Rage-fueled Roadblock sends a missile he fired right back at him.
Thomas the Tank Engine uses this a lot. Each engine model has a scared face that's absolutely perfect for this. Commonly seen when an engine's train becomes a runaway. A good one would be in "Old Iron". James is cruising along light engine (due to some naughty boys climbing into his cab and playing with his controls), enjoying himself. Then he notices he's going faster and faster, and realizes his cab is empty. "What shall I do? I can't stop! HELP! HELP!"
It's generally agreed, however, that the most infamous of all the Oh Crap faces is the "O" Face◊.
Dan Phantom gets one in the Danny Phantom episode "The Ultimate Enemy", when he's sent flying into a petrol tanker and quickly learns one of the drawbacks of having Flaming Hair, as the vehicle explodes.
In "Memory Blank", Danny himself gets one when he realizes that when Sam wished she never met him with Desiree is around to hear it.
In the Ben 10 episode "Ben 10,000 Returns", when young Ben as Waybig is hit by Eon's time aging ray and crumbles into a big pile of dust, Professor Paradox and Ben 10,000 both give a great open-mouthed oh crap face from a side view.
In the Chip 'n Dale Rescue Rangers episode "Seer No Evil", Monterrey Jack has one when he realizes that he, Gadget, and Dale are in a trunk, which is the last of the fortune teller's predictions that ends with Chip's death. He doesn't die after all.
Family Guy episode "Stuck Together, Torn Apart",. Brian and Stewie share this moment after getting their hands stuck together:
(Both read the industrial glue Never Comes Unstuck)
Also uttered by Peter when realizing that he is to fight Ernie the Giant Chicken for the third time.
Played with in the episode "Electric Eggs", after the Urpneys bump into Rufus and Amberley, expecting the worst, only for the latter to perform this trope as well and run for it.
Rufus, Amberley and Albert pull a particularly epic one in "The Dream Beam Invasion", when Frizz and Nug start growing to enormous size and give them quite a nasty glare.
Flint has this look in the G.I. Joe episode "The Gamesmaster" when, after challenging the Gamesmaster to a fight, the Gamesmaster stands up from his chair and is revealed to be over ten feet tall.
In the Mickey Mouse short The Pointer, when Mickey turns around and realizes that whom he thought was Pluto is actually a bear. While looking right into the bear's jaw.
In the Sorcerer's Apprentice short from Fantasia, Mickey gets the mother of all Oh Crap expressions on his face when he realizes that all chopping the broom to pieces did was make things worse.
In Jumanji the Animated Series Ibsen has quite a few of these, his response is often a small, weak "Oh dear" or some variation.
In Gargoyles, The normally unflappable Owen gets one when Anastasia Reynard says that she's remarried her first husband. Why this is is a mystery until both their true natures have been brought to light.
In South Park episode 6x11, the owner of the city wok does this absolutely according to the book: He gives a big speech, realises something's wrong, sees the fuse, follows it with his eyes, says "Oh Crap" and gets blown away, together with part of his wall.
Francine and Hayley can also get pretty creeped out by Stan themselves. They pull this off when realise how Stanreacts to criticism.
Transformers Prime finally gets in on the action. After doing everything in his power to prevent it, Megatron fails to keep Optimus Prime from obtaining the Star Saber, a legendary weapon that can only be used by a Prime. Prime uses the sword to not only cleave in two a mountain that was just dropped on him, but to fire a Sword Beam at the Decepticon warship. Megatron's reaction is less than positive, as he calls this the Decepticons' darkest hour.
Doyle does this (even going so far as to utter "Oh crud!") as he notices the time has run out on his emergency air supply in The Secret Saturdays episode "Where Lies the Engulfer".
The season 2 finale of Duck Dodgers has rogue Martian General Z-9 abduct the Martian Queen and steal Duck Dodger's ship as he leads an armada to Earth. However, it is not Z-9 who has the Oh Crap! moment, even when he realizes that he doesn't, as he'd hoped, have the satellite defense codes.
Counselor Dish:Shall we call off the attack, General?
General Z-9:Maintain course, Counselor Dish.
Counselor Dish:But, no Martian ship will make it through the shields. We'll be vaporized.
Twice in the episode "Meet Mr. Bogus" does this happen. Bogus gets one when he sees that part of the rafter that he had been skateboarding on had been gnawed away by Ratty, while Jake and Butch also get this reaction when they see the lawnmower, with Bogus on it, heading in their direction.
In the episode "Shop Around The Clock", the white rats get this reaction in the second act when they see the dalmatian head their way, intent to fetching the dog treat that Ratty threw on top of their cage. Bogus also gets one before getting hit by a blue squeak toy that Ratty and the white rats have catapulted at him.
In the third act of the episode "Museum Madness", Ratty gets one before Mole inadvertently knocks him off the plank of the pirate ship. He gets another one a little later afterwards when Mole also inadvertently causes the cannon to tip down while trying to fire a shot, before the shot causes the pirate ship to sink.
Bogus and Tommy both get this reaction in the first act of the episode "Lights, Camera, Bogus", when Brattus gets eaten by the robot dinosaur.
Two examples in the episode "Good Sport Bogus"; the Dirt Dudes both get this reaction in the first act when Bogus uses his spaceship to fire a stream of water that blasts them away, and Bogus himself gets a rather hilarious one in the third act when he sees the arrow soaring directly toward the archery target that he's stuck in.
In the first act of the episode "Computer Intruder", Bogus and Baddus both get this reaction upon discovering the huge and evil Bogus clone playing them for saps against each other.
This was Ratty and Mole's reaction near the end of the third act of the episode "Babysitting Bogus", when they realize that there's no way for them to escape the baby.
In the second act of the episode "Bookstore Bogus", Bogus gets this reaction before crashing into the bookshelf, while in mid-flight while pursuing Ratty and Mole.
Bogus gets this reaction when he realizes that he's about to get smacked by the tube of toothpaste that he just jumped over in the first act of the episode "Bad Luck Bogus".
Both Ren and Stimpy get one in The Ren & Stimpy Show short "Nurse Stimpy" when both characters don nurse outfits to take care of the other, Stimpy more than Ren when he realizes that Ren's doing it as revenge.