Wafer-Thin Mint

First, fill something to the nick of overfilling. It just doesn't matter what it is: a bag almost bulging with stuff; a cliff in its weight limit; an almost full elevator; a morbidly obese gourmand's stuffed stomach; you name it. When you've finished, add just a teeny, tiny bit more. Watch your recipient blow/crack/shatter instantly and/or loudly.

This trope applies to situations where maximal capacity is reached, and even an infinitesimal quantity surpassing it causes effects far more massive than common sense could predict.

Although the most common variation of this is when a group of people/stuff is at a ledge and a light feather/dust powder lands and it simply breaks apart instantly(and painfully), it's not only restricted to those cases. Also, it's not restricted to animation only, as the above example points out.

Known in popular culture as "the last straw" or "the straw that broke the camel's back," which also has another meaning: the Rant-Inducing Slight. Compare Death of a Thousand Cuts, Critical Existence Failure and Critical Encumbrance Failure.

Comic Books

 * In Carl Barks' Donald Duck comics story "A Christmas For Shacktown", Scrooge's money bin has become so full that when he drops in just one more dime, the ground under the bin caves in and all of his money falls into a practically bottomless pit. We don't find out how he got it all out until Don Rosa's story "Gyro's First Invention".
 * FoxTrot did a variation as a Shout-Out to the Trope Namer, with Peter and Paige's heads bloated from an all-night cram session (and a viewing of Meaning of Life) and Jason offering them "onlee a wafer-theen formula".

Commercials

 * The US commercial for Super Mario World 2: Yoshi's Island is similar to the scene from The Meaning of Life, with a man eating a huge amount of food to represent everything that was crammed into the game. When he's full, he has a bit of whipped cream or something (to represent a bonus level) and ... kablooie. Which soon got censored after it first aired. In the original versions of it the dude is seen exploding. Censored versions had him exploding off screen.
 * A 90's commercial for a car had a man on a step ladder pouring soda into a very fragile bucket to represent the amount of gasoline needed to power other brand cars. He continuously pours more soda in to represent every stop he makes to get gas. When the bucket is about to overflow, the narrator tells him to get some gas "for the trip back home". Guess what happens next?
 * Two Australian men have loaded a pick-up truck to capacity with Castlemane XXXX beer. They add a couple of bottle of sherry for the ladies, and the truck's groaning suspension finally collapses. Of course, they conclude it was too much sherry.

Eastern Animation

 * In one of the episodes of Nu Pogodi, the Wolf had barely managed to lift a very heavy barbell, when a butterfly lands on it, with predictable results.

Film

 * Monty Python's The Meaning Of Life. A literal mint was used in this one, and effectively makes this the trope-namer. See the dialog on Wafer-Thin Mint/Quotes.
 * In the movie Jack, the treehouse where a bunch of kids, Robin Williams as a forty-year-old adult that's actually a kid with severe growth problems and Bill Cosby singing and stomping feet falls down when a butterfly lands on not even the treehouse itself but a splinter, which slowly bends until it touches the treehouse, and then everything falls apart.
 * In True Lies the bad guys' truck is hanging off the edge of the bridge and they sigh in relief that it didn't go over.
 * James Bond movie For Your Eyes Only: Car is poised on edge of cliff;  walks up and tosses  a pin at the car. Expected results, but the car doesn't fall. In a subversion of sorts,  gives the car a kick for good measure.
 * Used twice with Pip in Enchanted. Once by accident, the second as a kind of Heroic Sacrifice. (But it was a Disney movie, so...).
 * In Beetlejuice, Adam and Barbara are driving over a covered bridge and swerve to avoid a dog. They crash through the wall of the bridge and end up poised on the edge, teetering above a river. They look back and see the dog standing on a broken plank, panting happily at them. The dog hops off the plank, and over they go.
 * In Black Sheep -- the David Spade/Chris Farley comedy, not the horror-comedy with mutant sheep -- a huge boulder behind the cabin in which the two main characters are staying is loosened by, among other things, David Spade's character standing on it and a rodent digging under it. Finally, a bird flying overhead poops on it, and...
 * Spy Hard: In a flashback, Steele makes a false presidential rescue thinking there's a threat. He ends up having his feet hanging over the ledge of a bridge along with the president's car. He stretched his arms out with his wallet to keep himself from falling.
 * In the film of Wizards of Waverly Place Justin has to make a bridge. He's very proud of it and taunts Alex until she wordlessly takes a pebble and tosses it on the bridge. The Genre Savvy can guess what happens.
 * Idiocracy: A truck adds to a massive pile of garbage. It gets compressed, but stays intact; Then a single can falls out of the truck, triggering an avalanche dozens of meters high.
 * Road Trip: Seann Scott's character demonstrates he can spit across a ten-foot wide broken bridge. He did, but causing the other end of the bridge to collapse from his spit.

Literature

 * In the Discworld book Interesting Times, Rincewind is dangling above a giant fall, barely supported by a few rotting logs. A quantum butterfly lands on his hat, and, wary of this exact trope, Rincewind tries to blow it off - so it starts making it rain just over his head, which is enough to drop him. It also stings him with a very small lightning bolt.
 * In Dombey and Son, Charles Dickens says, 'As the last straw breaks the laden camel's back,' making this trope Older Than Radio.
 * The children's book The Mitten is about a small boy's mitten that gets dropped in the woods. First a little mouse finds the mitten and finds it a cozy nest. Then along comes a small frog, and then a rabbit, and the mitten is pretty much big enough for them, and quite warm. Then things start to get out of hand when a fox, then a wolf, and then a bear arrive and clamber for space in the mitten. Finally a doddering granny grasshopper comes along and blows off their cries of "No room! No room!" by saying, "There's always room for one more!" She nudges in one foot and the mitten goes plooie.
 * In the Jan Brett version, the animals start with rabbit, and the mitten doesn't explode until a mouse snuggles herself on the bear's nose.
 * Similarly, in the picture book "Who Sank the Boat", every time an animal gets in we're asked "Do you know who sank the boat?" The answer, of course, isn't one of the big animals but the little mouse, the last to get in, the smallest of all.
 * The Annie M.G. Schmidt poem De brug bij Breukelen (The bridge near Breukelen) has everyone and everything going over a bridge safely, until a mosquito lands on it...

Live Action TV
"Cameron: The weight limit's obviously just an estimation. It's not like it can hold 450 pounds fine and then collapse under 451.
 * 8 Simple Rules: CJ stands on the trap door to the attic, holding a bowling ball and a teddy bear. He drops the bowling ball so the trap door would go up. Nothing happens. He drops the teddy bear, and then the trap door goes up.
 * In the ICarly episode "iDate a Bad Boy" Spencer buys a pressure sensitive alarm in front of the door to prevent Carly from sneaking out. Carly jumps up and down on it, and it doesn't go off. Later, an obese postman comes to give a package to Spencer, telling him that it needed one more stamp. The postman steps on the sensor with the package. Nothing. Spencer gives him the stamp to complete the postage, and then alarm goes off.
 * Seinfeld: George's wallet. The "mint" is a phone tab from an ad (a strip of paper just big enough to fit a phone number).
 * House: Played with; the team has to diagnose a morbidly obese man in a coma. They eventually get to the point that they need to get an MRI. Only problem? The weight limit for the MRI is 450. The man in question weighs over 600.

Chase: He's not 1 pound over, he's 150 pounds over."


 * Surprisingly, the MRI machine held until the patient woke up whereupon he promptly broke it via struggling to get out.
 * The Myth Busters have tested the "bird landing on a car making it fall" scenario. (Busted.)

Video Games

 * In Nethack, once you've eaten enough to become satiated, eating (almost) anything will give you a warning. If you keep trying, you may choke to death. This includes the corpses left by wraiths, which are incorporeal. Note that it's only possible to survive if you're wearing an amulet of magical breathing.
 * This is actually referenced on "Lessons Learned the Hard Way," which is Exactly What It Says on the Tin: "Don't eat wraith corpses when satiated. You don't get a warning."
 * Kingdom of Loathing: "You eat the piece of after eight. Despite the wafer-thinness of the mint, you explode in a shower of gore."
 * All but lampshaded in Devil May Cry 4, when Dante explodes a huge towering Boss with one hit point left with a single pistol bullet. Twice.
 * CJ in Grand Theft Auto San Andreas can eat up to eleven super-size fast food meals perfectly comfortably. Try finishing it off with a salad though...
 * In The Elder Scrolls IV: Oblivion, you can run at full speed while being 0.1 weight units under your limit and preform stunning feats of acrobatics if your level is high enough, but if, in that state, you get hit by a 0.1 weight arrow, you are instantly immobilized.
 * While not quite the same thing, in Breath of Fire 4 the God-Emperor Fou-Lu has spent the entire game with a target on his head by the very empire that resurrected him. Near the end of the game, they decide to go all out  This act effectively convinces him to go from Humans Are Bastards but he can live with it to Kill'Em All and then burn the world down.

Web Comics

 * In The Inexplicable Adventures of Bob, Galatea is eating at a posh French restaurant and making her usual complete pig of herself. In a shout out to Monty Python, it turns out the long-suffering waiter fed her The Wafer Thin Mint some time ago, to no effect, and she orders another plate-full of them, just to emphasize what a bottomless pit her stomach truly is. After the meal, she skips out on the check.

Western Animation
"Bugs: I'll do it, but I'll probably hate myself in the morning."
 * More than once in classical WB, MGM and Disney cartoons.
 * Frigid Hare: Bugs and the big bad Eskimo are hanging onto a broken off ledge that is literally swinging in the wind. The penguin looks down at them, accidentally dislodging a single snowflake which drifts down onto the ledge...
 * The classic Goofy bodybuilding sketch in Goofy Gymnastics. He's holding up a weight that he can barely hold. A fly lands on one end, he starts to tumble, but stays up. The fly walks across the barbell, and at that time he falls through the floor.
 * An example of the explosion version: In the early Looney Tunes short Pigs is Pigs, a young pig (not Porky) dreams he is being overfed by a Mad Scientist. As he leaves, stuffed to the gills, he takes a bite off a drumstick and...Kaboom!
 * Implied at the end of Chuck Jones' Chow Hound: "This time, we didn't forget the gravy!"
 * Bugs Bunny sets it up in Little Red Riding Rabbit, by piling a bunch of goods on top of the big bad wolf, who's straddled right over a bunch of hot coals, but just as he's climbing up a ladder to invoke the trope with a feather... LRRH shows up. Red is, in this case, a Genre (or at least Story) Savvy teenager with a loud, obnoxious voice and a fairly clear idea of how things go. She's been spending the entire short harassing Bugs and the wolf ("Hey Grandmaaaaa!"), and her barging in while Bugs is busy is a Wafer Thin Mint all on its own. Bugs abandons his attempt to roast the wolf in favor of leaving Red at the bottom of the pile, while standing off to one side sharing a carrot with the wolf! That seems a bit harsh, even for Red.


 * This gag happened frequently on both Tiny Toon Adventures and Animaniacs, possibly in reference to its frequent use in Looney Tunes. In one of many examples from Tiny Toons, Babs adds "I just can't help myself" as she delicately places a single rose on top of a gigantic pile someone is carrying. Guess what happens.
 * The Simpsons used it to great effect in the "Mr. Plow" episode, when a vehicle is peering off the edge of a road, about to topple in sideways. The saving gesture? Turning the radio dial to the left, causing the vehicle to flop back onto the road.
 * An animated segment on Sesame Street featured an elevator where first the operator, a fairy, soldier, witch, kangaroo, taxicab, fireman, clown, gorilla, and a mouse get on board. When the mouse gets on board, the elevator shakes and then explodes, sending the operator falling to the bottom of the shaft.
 * Another example: a kid yanks the bottom can of a stack and the whole store collapses.
 * Stitch of Lilo and Stitch can lift three thousand times his own weight, but collapses under even a little bit more. This was dramatically demonstrated in one scene where he is lifting ten girders and two bulldozers. The bad guy comments, "You can lift three thousand times your own weight and not an ounce more." He then proceeds to throw his backstage pass on the pile, causing a total collapse.
 * Gone Nutty, a short starring Scrat from Ice Age: Scrat has filled a log full of acorns and is just putting in the last one. But the log is so full that that last acorn keeps popping out. In trying to push it back in, the bottom collapses, sending all the nuts - and Scrat - tumbling down a cliff.
 * One episode of DuckTales has the Beagle Boys mounting a full-scale offensive on Scrooge McDuck's Money Bin. Bigtime Beagle shows up wearing a full suit of armor; Scrooge shows up driving a tank. Bigtime crows that his armor can withstand a 60mm shell; Scrooge responds by saying that his tank fires 61mm shells, and after counting on his fingers Bigtime figures out "That's one millimeter too many!" True to the trope, he takes the shell full-on and gets sent flying out of the Money Bin.
 * Thanks to the Square-Cube Law, this wafer's slightly more than wafer-thin; assuming it's the same shape, the thing would be about 11,000 mm^3 larger.
 * In the Veggie Tales episode Madame Blueberry, the titular character goes on a major shopping spree and has everything she purchases sent to her opulent treehouse mansion while she keeps shopping, unaware of how much she is really buying, and that each item is sending her house closer to its demise. Eventually she catches on, and manages to stop the deliveries, but only once the house has just enough stuff in it to stabilize. And then, a butterfly lands on the roof, tipping the treehouse and depositing all the stuff she bought into the lake.
 * Cloudy with a Chance of Meatballs: the dam holding back the mountain of leftover food gives way when a single cherry falls on top of a scoop of ice cream.
 * Rocky and Bullwinkle: Boris and Natasha overloaded the raft with supplies from Moosylvania. Fearless Leader shows up from his sub awarding Boris with a one ounce medal, enough to sink their raft.
 * In a song in the 3D children's cartoon Word World, Pig makes a pizza with toppings that all start with the letter P. He stacks the pizza up with "toppings" ranging from popcorn to pickles, creating a tower of various foods. Finally, he adds a single peanut, causing the entire tower to fall.
 * In an episode of Doug, Doug and Mr. Fink aboard the fishing boat overloading with all sorts of mostly unnecessary equipment. Not until Mr. Fink needed the keys in which his wife tossed them to him enough to sink the boat with them on board.
 * Futurama: In the "Put Your Head on My Shoulder" episode, Amy takes Fry for a ride in her new car on Mercury. They proceed to run the fuel down by turning on all the appliances (including turning on the heater to counteract the air conditioning). The final straw is not when Fry puts Pop-Tarts™ in the toaster but rather when he turns up the darkness control on the toaster!
 * The Angry Beavers: In one episode, a tree that has been growing since the time of the dinosaurs teeters on the edge of a cliff due to millions of years of erosion. Finally, a single fly lands on an exposed root-sending it toppling right into the protagonists' house.
 * American Dad did a cliff-side variant in "Delorean Story-an". During a father and son road trip, Stan overinflated and burst his bubblegum at his face losing control and causing his car to nearly fall off a cliff. They manage to get out safely while the car is still in balance, until a Japanese motorist from an earlier encounter arrives and slightly adjusts their crooked side mirror causing the car to fall off the cliff.
 * True to its Looney Tunes origins, this trope shows up in Taz-Mania. In the first appearance of the Kiwi, Taz and Buddy Boar end up tied to a tree dangling over the edge of a cliff. The Kiwi returns Buddy's lucky coin, which it had stolen earlier, and the extra weight is enough to cause the tree to snap.
 * In My Life as a Teenage Robot, a hackeysack adds enough mass to an asteroid to make it a threat.

Real Life

 * Jenga.
 * Not to mention Buckaroo.
 * The Paradox of the Heap intentionally takes advantage of most people's tendencies to ignore the Wafer-Thin Mint.
 * A riddle features a clever aversion of this. Suppose a truck weighing one tonne at the start of its journey (including the driver) is driving across a bridge with a weight limit of exactly one tonne. Halfway across the bridge, a robin weighing 75 grams lands on the bridge. What happens?
 * Other riddles play it straight. One man weighing 248 pounds is carrying three 1-pound coconuts, and needs to cross a bridge with a weight limit of 250 pounds. How does he do it?
 * Alternatively,.
 * Regardless of which riddle is chosen, in reality bridges are posted with a weight limit below their actual maximum load - in order to ensure that bridges won't snap simply by adding a straw to the load.
 * If you supersaturate a solution--dissolve something into a solvent (e.g. water) so that there is more of the solute (e.g. sugar) present than there could be under normal conditions--adding the tiniest amount of the solute into the apparently clear liquid will cause it to crystallize, as the added crystal provides a seed for the excess solute to grow upon. This is beyond annoying, among other things, when you are trying to make toffee.
 * Useful, though, in chemical heat packs. Just snap the enclosed metal disc inside out, the mechanical shock seeds crystallization, and the pack releases the stored heat of the solution.
 * To those more chemistry-savvy, the action described above is referred to as "falling out."
 * Analogously, homogeneous fluids in clean, smooth containers can under some circumstances be heated beyond their normal boiling point without boiling. Disturbing the fluid sufficiently, or introducing nucleation points, can then cause flash-boiling and potentially a small steam explosion.
 * Also, changing its pressure can cause it to boil. This, combined with the fact that evaporating liquids absorb heat, is very useful for refrigeration.
 * This was shown on Myth Busters, it happens most often in everyday life by somebody trying to boil purified water, usually in a microwave, will explode if you put anything into it.
 * Equivalent to the superheating described above, you can also supercool a fluid below the freezing point in a clean, smooth, container. Adding a nucleation site (or even just jolting the container) can cause it to instantly freeze.
 * Also examined on Myth Busters, by supercooling beer and then rapping the bottle on a solid surface to cause it to freeze.
 * As listed on the page introduction, another title for this could be "The straw that broke the camel's back". This refers to a folk-tale that was persistent in both the Middle East and North Africa. According to the tale a camel could only carry XX kilograms of supplies, and anything more would be too much. While the story is obviously not 100% true, like many folk-tales, it has a grain of truth to it. Apparently, caravan drivers were able to figure out close to the max weight that a camel could conceivably carry.