Corpse Bride does this twice. First, the opening song, "According to Plan", is all about how "every tiny microscopic little thing" must be just perfect for the wedding. You couldn't be asking for it more. Then, later, when Barkis is making his wedding toast, he says, "No force on Earth can tear us apart!" Cue the invasion of the walking dead.
"We're superheroes. What could happen?" Actually happens twice, with the same result.
"Don't worry Mrs. Parr. I can handle anything this baby dishes out..."
"This is not the end of it! I'll get your son eventually! I'll get your son!" Seconds later, Bob makes sure it's the end of it and Syndrome is introduced to the business end of a jet turbine.
Finding Nemo: "No, I've never met a shark, and I don't plan to."..."Well, if I ever meet a sea turtle, I'll ask him... right after I'm done talking to the shark."
The Princess and the Frog: "I've climbed a mountain, I've crossed a river, and I'm almost there!" To be fair, she had already made it past a number of obstacles — being a young, black, poor, woman... It was just that the magic took it to a whole new level of obstacles, and she couldn't have anticipated that!
In the Hungarian cult film Cat City, mice are on the good side, and cats are criminals. At the beginning, a bank clerk assures a worrying client that to this bank, cats could only break into with a tank. Guess what happens next. And his very next line...
While Roger is standing guard inside Maroon Studios he says "No one gets the drop on Roger Rabbit!" Seconds later he's conked on the head and knocked out by a frying pan.
Lampshaded later when Jessica says the only reason she knocked him out and stuffed him in the trunk of a car was because she didn't want him getting hurt. Lampshadeded again when Eddie responds with obvious irony, "Yeah, that makes perfect sense."
Kung Fu Panda: "Escape from Chor-Gom Prison is IMPOSSIBLE!" Tai Lung likes a challenge
Tai Lung taunts Po with "What are you gonna do, big guy? Sit on me?". Shortly after, both Po and him are tumbling down the mountain stairs and Po lands on his head.
A Bug's Life has Hopper tempt fate upon seeing a bird standing right above him. To be fair, fate was Crying Wolf earlier on, seeing as how the last bird Hopper saw before then turned out to be a fake one designed by Flik, and said bird showed up while Hopper was trying to strangle Flik. Still, it is interesting that his last words (aside from the screaming) were being said to Flik upon them seeing said bird...
Yellow Submarine. Ringo says "Nothing ever happens to me." Cue the title vehicle's appearance.
The Aristocats: "You're going to Timbuktu, if it's the last thing I do!" (cue a bunch of alley cats led by Thomas O'Malley subduing Edgar, then shoving him into the very crate he was going to use to send Duchess and her kittens to Timbuktu, and as a result, it's now Edgar that's the one going to Timbuktu)
Towards the end of Disney's The Hunchback of Notre Dame, while Esmeralda is holding Quasimodo up over the edge of a building, while Frollo close by is standing, above a pool of molten copper, on a stone gargoyle, while carrying a sword, and says "and he shall smite the wicked, and plunge them into the fiery pit!" Remember what happened after that?
The premise of the song "I Just Can't Wait to be King" from the film The Lion King. Unfortunately, becoming king has a fairly drastic requirement...
In Shrek the Third, Shrek is called to King Harold's side. Already annoyed by the kingly duties placed on him during Harold's sickness, he yells, "Someone better be dying!" That someone turns out to be Harold himself.
Pinocchio. "Hear that beetle talk; you'd think something was gonna happen to us." Cue Lampwick turning into a donkey.
The song "There Are No Cats in America" from An American Tail. However, it turns out that there are cats in America.
In the 2012 version of The Lorax The Once-ler delivers the line "I intend to keep biggering and BIGGERING, and turning more truffula trees into thneeds! AND NOTHING IS GOING TO STOP ME!" right before the final truffula tree falls.
Perry Babcock: Where are the police when they are needed!? Sheriff Hopkins crashes her motorcycle into the Babcocks' car, slides across the car and rams into Perry.
In another example, Norman arrives at the graveyard near Mr. Prederghast's home with the book, and reassures himself that all he's got to do is read it, stop the curse, and then go home and continue life as usual. Sounds easy enough. Except he's reading it in the wrong spot. The curse goes off anyway, causing all hell to break loose.
Hoodwinked: Red is riding a cable car with Boingo.
Boingo: Hey, you deliver up this far?
Red Puckett: Well, not usually. But I was thinking about what you told me earlier - about the Muffin Man? I need to protect Granny's recipes from that bandit's evil plan. They're gonna shut down everyone in the forest if we're not careful.
(Cue tram car doors flying open and Red struggling to keep her balance)
In Frozen, Queen Elsa declares during her song "Let It Go", "You'll never see me cry!" She does cry, when her sister Anna seemingly sacrifices herself to save her. Fortunately, Anna lives.
In Monsters University, Oozma Kappa comes last in the first event of the Scare Games, meaning that Mike now has to leave the university, and Dean Hardscrabble taunts that only a miracle could have saved them. Before she even finishes her sentence, the judges reveal that one of the fraternities cheated at the event and are disqualified, allowing Oozma Kappa to remain in the games.
Monsters, Inc.: When Mike and Sully are fleeing to their apartment after Boo gets loose in the sushi restaurant Mike was taking Celia to, he comments that he doesn't think it could've gone any worse. Following this, the CDA encases the surrounding area behind them in a decontamination field.
South Park: Bigger, Longer & Uncut. After the Baldwin family's home gets bombed by the Canadian Air Force, all of them are dead except for a single survivor. He triumphantly boasts "Ha ha! You missed me!" right before the last plane drops a bomb on his head as well.