In the Animaniacs episode "Bumbie's Mom", after Slappy Squirrel has cheered Skippy up from the trauma of Bumbie, on the plane ride home they watch the in-flight movie, which turns out to be Old Yellow. Slappy gives an Oh, Crap! face when we hear the titular dog being shot, and then she flatly comments "Uh-oh," not amused by what's about to happen (Skippy bawling loudly again.)
Batman gets one. Upon realizing that, not only is a character who can only combine two non-human animals going to try to combine three, he's going to combine them with Batman himself, his only response is:
Batman:[deadpan] Oh, no. [turns into a griffin.]
Joker also gets a humorous deadpan one in "Game Over for Owlman!" where he serves a Wild Card for most of the episode. At the climax of the factory fight, Batman pushes Joker and Owlman together, prompting them to bicker due to differing personalities...until the smoke clears and they realize that Batman positioned them under a giant cement sprayer.
Joker:[looking up, drolly] ...drat. [both are instantly covered in quick-drying cement as Owlman tries to strangle Joker.]
In Beast Wars, one of Rattrap's catchphrases is a resigned "We're all gonna die."
While the usual response to that is an annoyed "Shut up Rattrap!" from everyone else, the final episode had the Ark being pulled up by the reactivated Nemesis into what looked like a gigantic bladed shredder:
Rattrap: We're all gonna die. Rhinox: Yup.
The episode before that had The Chew Toy Waspinator dragged into yet another misadventure. While ever the complainer, this time he invokes the trope:
Rhinox: Oog... wild bean vines... hard to digest. Megatron: Do not turn your back on me, Maximal scum! (The Maximals, realizing the situation, back away nervously and move upwind. Even Dinobot.) Megatron:(finally realizing, covering his face in abject horror) Oh no... not that! AUUUUUUGGHH— (Cue Distant Reaction Shot of an enormous blue atmospheric bloom of energon vapor the size of Africa.)
In episode "Negative 10 Part 2", when Rojo and the Circus Freaks are tricked into attacking a hologram of the kids and realize too late that it's actually a bomb, Acid Breath simply deadpans, "I hate those guys" before the device goes off.
An earlier episode, "Hunted", featured this with the bounty hunter Kraab. His cybernetic body disabled thanks to Grey Matter, he says this a few seconds before a water tower falls on him and SixSix:
Kraab: I hate this planet.
In the Alien Force episode "Con of Rath", the Vreedle brothers have this response just before getting thrown off a space station by Rath:
Octagon: This is gonna hurt, I suspect. Rhomboid: (after the fact) Well, that didn't work out so good.
Chowder: In "Grubble Gum", Gazpacho has one when he looks up to see a city-sized ball of bubblegum, buildings and people falling out of the sky to crush him, along with the trapped title character cheerfully shouting "Hi, Gazpacho!" His surprised expression only lasts for a fraction of a second. After that, he reacts with a simple "I regret nothing" right before he gets hit.
Code Lyoko: While what he actually says is "I promise never to complain about not having conflicts with my parents again," Odd Della Robbia's expression and tone as he waits for his Brainwashed and Crazy parents to toss him off the school roof screams this trope.
One Curious George episode has an ending involving an elevator, a man with a timid pet skunk, and a radio about to switch from smooth jazz to "highlights from the 1812 Overture". Quoth the Man with the Big Yellow Hat: "Oh, no."
In one Darkwing Duck episode, Megavolt gets a particularly whiny "Aww, this is gonna hurt," after being thrown off a roof.
Happens frequently on Dastardly and Muttley in Their Flying Machines. Most notably when the Vulture Squadron's plane is turned invisible with Klunk's invisibility spray. It rains, washing the spray off and making the plane visible again, but the Squadron doesn't know it. Dastardly aims a cannon at Yankee Doodle Pigeon, who merely tips it back in their direction. Dastardly can only mutter "Oh, no!" before the Squadron gets blasted.
After Peter gets booted off the Patriots Football time and transferred to the London Silly Nannies. After he sees what kind of team they are his expression as follows:
Peter: Aw, Crap.
In "Spies Reminiscent of Us", Peter, Joe and Quagmire decide to perform an improv routine. From the very first brainstorm over their group name, Peter's idiocy and Quagmire's finicky attitude to the routine tells Joe right off the bat how things will go down:
Joe: I can already tell this is not going to be fun.
In the crossover with The Simpsons, when Peter and Homer were fighting in Kang and Kodos' ship, the ship is heading right for the Springfield Gorge.
Peter: I think we're gonna make it! Homer: Trust me, we're not.
Professor Farnsworth: Anyhoo, your net-suits will allow you to experience Fry's worm infested bowels as if you were actually wriggling through them. Dr. Zoidberg: (cheerfully) There's no part of that sentence I didn't like!
In the episode "Hereafter", Batman is standing toe-to-toe with Kalibak, who taunts Batman by saying there's no way Batman can beat him. Bats simply replies "I'm not trying to beat you. I'm trying to stall you." When Kalibak asks what for, that's when Superman hovers in down behind him. Kalibak manages to say "Aww-" before getting smashed halfway down a city block and into a building.
A similar thing happens when Gorilla Grodd realises his mental attacks have little to no effect on Superman... right before Supes flicks him into the air.
In "Date Night" Black Canary is chasing Huntress and The Question on a motorcycle. When Question leaps his car off a giant ramp, Canary moves to follow; Green Arrow looks away and mutters, pained, "This is sounnecessary."
In "The Once and Future Thing (Pt. 2)", one of the Jokerz (a gang from the Batman Beyond-era Gotham) gets deposited by a time-travelling supercriminal back in the prehistoric era for his betrayal. He gets ready to tangle with a Tyrannosaurus, declaring how he'd be running the place soon enough...when he sees the dino-killer asteroid coming into Earth's atmosphere. His response is nothing more than a dejected, "Ahh, phooey."
In "This Little Piggie", Circe reacts to seeing that Zatanna has telekinetically thrown a piano at her with a quiet "oh no" just before it hits.
Kaeloo: In the show's first episode, "Let's Play Prison-Ball", this is Mr. Cat's reaction to realizing he pushed Kaeloo past the limit and is in for a No-Holds-Barred Beatdown.
Ron Stoppable in has a variation of this trope line when he sees something that could very well do the duo in (but, to him, looks freaking awesome), saying, "That would be so cool if..." followed usually by "it wasn't going to hurt us."
There are variations of it, with the most obvious change being in the So The Drama movie, when Ron comes face to face with the full size Diablo for the first time, possibly in response to the movie being the would've-been series finale.
Ron: That would be so cool if it wasn't the last thing we were ever gonna see.
Draken's various "Oh, Snap!" moments occasionally fall into this territory. There is a particularly elaborate one in the climax of Odds Man In, as shown below:
Draken: [With a tidal-wave of batter heading towards him] This is going to negatively impact third quota performance!
Brainiac 5: This is going to hurt. [The whole ship explodes]
Looney Tunes characters display this trope right before being pummeled.
Wile E. Coyote, being mute, often holds up a sign saying "YIPE!" or something similar (like writing his will during a long drop) just as he's about to get hammered or take one of his very long falls. He even manages a completely wordless one when he simply holds up a tiny umbrella and winces while in the shadow of a falling boulder.
When Sylvester tried disguising full-bodyas a female dog as part of a plan to pummel Hector the bulldog to get access to Tweety, his suit and mask was so good it fooled a dog catcher. Inside the dog catcher's wagon, Sylvester tried to explain to the catcher that he was a cat and removed his mask in front of a bunch of dogs. Seeing the predicament he was in, Sylvester turned white and melted down...
In The Loud House episode "Cover Girls", the Loud children get this expression on their faces when Lynn Sr. and Rita tell them that their punishment for lying to Pop Pop would be having to go back to their activities while dressed as the sibling they were last covering for.
In the Mickey Mouse (2013) episode "Movie Time", Mickey braves a huge storm to reach his house, only to see a huge tidal wave coming after he finally gets there. His reaction is a half-resigned, half-exasperated "Oh.".
In "Lesson Zero", Twilight Sparkle becomes persistent in mailing a friendship lesson to Princess Celestia, and begins a search around Ponyville for anyone suffering a problem concerning friendship. Spike rightfully predicts the result:
ReBootaffectionately parodies the Looney Tunes invocations in the episode "Between a Raccoon and a Hard Place." Just before getting steamrolled, Rocky the Rabid Raccoon says "This is gonna hurt!" As his squashed self rolls back into view on the steamroller wheel, it holds a sign reading "Told Ya!"
"A Star Is Burns": Chief Wiggum, upon realizing his tie is caught in Apu's hot dog roller, simply comments "Oh boy, this is going to get worse before it gets better."
When France launched a nuke at Springfield in the "Treehouse of Horror VIII" segment "The Homega Man", the camera follows the path of the bomb... directly into Comic Book Guy's stomach. After walking down the street complaining about a comic book, he looks toward the missile and simply says "Oh, I've wasted my life." Mayor Quimby gets his own: "I bet I'll get blamed for this."note It was his fault
The "Treehouse of Horror V" segment "Time and Punishment" has Homer repeatedly bouncing from his current time to the prehistoric era, and was told about the butterfly effect and its dangerous effects on the timeline. Even minor infractions such as accidentally killing one insect or animal lead to disaster...but when Homer sneezes and inadvertently causes the extinction of the dinosaurs, all Homer can forlornly get out is, "Thiiiiiiis is gonna cost me..." At another point in the same episode, Homer is trying desperately to avoid touching anything, seemingly succeeds and sits down in relief... on top of a lungfish. "Oh I wish, I wish, I hadn't killed that fish!"
In "Please Homer, Don't Hammer 'Em", Bart finds out that Principal Skinner is allergic to peanuts and uses it against him. At one point, he forces Skinner to put fireworks and cats in his pants, to which he says "This is not going to end well".
In the Sofia the First episode "King For a Day", after James decides the answer to a snoring sleeping giant is fireworks loud enough to drown him out, Baileywick comments, "I have a bad feeling about this," and Sofia adds, "I have a worse one."
Dr. Octopus: Now then, arachnid, Any Last Words? Spider-Man: "Homina homina homina" comes to mind.
In the second Sinister Six episode Spidey jumps on a frozen part of the sea luring his enemy, Rhino after him. Rhino jumps on the ice.. And realizes what he's just done, as the ice breaks beneath him he looks at Spidey and says: "...I hate you. So much." and he sinks straight through it.
Steven Universe: In "Change Your Mind", Rhodonite's reaction to stepping off her ship to see the last thing she ever wanted to see, namely, all three Diamonds in person waiting there, is to deliver the Gem equivalent of "well, we're dead" in tone of total resignation.
On Supernews President George W. Bush has to announce the latest plan for the Iraq War after a succession of failed plans... and he whines during the practice run about just how much This Is Gonna Suck.
Titan Maximum: Has it in the first episode when the caretaker of the Aviation Disaster Museum was about to be killed by a destroyed plane:
Caretaker: (looks up) Oh this is ironic as hell!!!
One episode of Tom and Jerry, "The Dog House", has Tom and Jerry's usual chase sabotaging Spike's attempts to build his dream dog house. At one point, he gets desperate enough to put the house in a tree, only to have Tom come after said tree with an axe after Jerry climbs it. Spike looks grumpily as the tree falls down, unmoving from his place, and all he says is a deadpan "Timber."
Transformers: Animated: In "Sound and Fury", when Bulkhead decides to participate in the piñata-breaking at Sari's birthday party, Prowl deadpans "This will not end well." Cue destruction.
In the episode "The Incredible Mr. Brisby", Doctor Venture, tied up in a sack, hears Brock Sampson, who's just been drugged, hit the floor, and responds by calmly saying, "Tttthhhat doesn't sound good."
In another episode: "Oh crap, Myra's back."
In Villainous, at one point, Dr. Flug weaves past the external security system and all its guns...only to be laser-painted by the internal security system as soon as he gets in the door. His response is simply to quietly fold into a Troubled Fetal Position, essentially saying this without words.
Wakfu: Nox has such a moment during the fight against Grougaloragran in season 1 episode 17, just before the Dragon uses his Breath Weapon on him at point-blank... with enough power to wake up all the volcanoes of the island.
Nox: Ehehe... well, at least it won't hurt much. (closes eyes)
In A Fine Feathered Frenzy, this is the expression on Woody's face when he realizes he'll have to marry Gorgeous Gal.
Yin Yang Yo! had Yang say this word for word while Yo was training him in the "Super Secret Training Shed." In response, Yo told him that he was probably thinking of the "Super Secret Shedding Train," which is a train that somehow makes any of the Anthropomorphic Animals that ride it to shed all of their fur.
During a season 2 episode of Young Justice, Captain Cold flash freezes an entire city block so he can rob an armored car. What he wasn't aware of is that he froze an area where seven members of the League and team were having a get-together. When they make the scene, he doesn't even pretend he has a chance.