Reminder of Impossibility

Stinkbomb: Ah ha!
Slappy: Hey! Isaac Newton. Interesting bit of trivia for you.
Stinkbomb: What's that?
Slappy: Dogs can't climb trees.
Stinkbomb: Oh.

— Animaniacs

Nature is funny sometimes. In media, people may actually be able to briefly perform a task they naturally can't for the sake of comedy until they are reminded that they don't have the ability to perform the action in question. The reason they start performing an impossible action in the first place is that they are so determined to achieve it that they forget they can't do it.

Of course, once they are reminded that they can't, they may immediately give an Oh, Crap! expression before reality kicks back in. Any moment where somebody does something that shouldn't even be possible applies if it gets pointed out and they immediately stop doing it or it stops working.

May be subverted if the reminder is there and the character involved still goes on doing their improbable thing.

Often overlaps with Gravity Is a Harsh Mistress when the thing they forgot was gravity or the end of the ground beneath them.

Compare Centipede's Dilemma, which involves a question on their ability rather than a genuine fact on their inability, Forgot I Couldn't Swim, when a character remembers their inability to swim upon jumping into water, This Cannot Be!, and Puff of Logic, which points out their inability to live or even exist. Compare Achievements in Ignorance, which tends to set up this trope, and contrast Forgot I Could Fly.

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Examples:

Advertising

• Soaky was a 1950s/60s kids' bubble bath in containers resembling cartoon characters whom themselves appear in the TV commercials for it. One spot featured Superman and Tennessee Tuxedo. In it, Tennessee is in midair flapping his hands as Superman flies up next to him:
  Superman: Tennessee, penguins can't fly!
  Tennessee: I happen to be skydiving.
  Superman: Without a parachute?
  Tennessee: [plummeting suddenly] I knew I forgot something! [Superman catches him]
• Vince the Crash Test Dummy manages to drive — until Larry reminds him he can't — in this 1988 commercial from the U.S. Department of Transportation.

Anime & Manga

• Naruto: During a filler arc, Naruto is hidden in a palanquin and carried away from the village by his fellow ninjas. However, the antagonist quickly locates them and starts knocking the heroes out one by one. Neji and Kakashi shed tears for their fallen comrades, until the latter realizes that, since they are the only ones left, they can't possibly support the palanquin's weight, causing them to immediately fall to the ground.

Comic Books

• Monica's Gang:
  • One comic has a random dog steal Maggy's bread bag and carry it up a tree. Instead of giving chase, the young girl triumphantly smiles and proclaims that dogs can't climb trees. This causes the animal to fall to the ground, allowing the protagonist to easily reclaim her stolen food.
  • In a storyline that parodizes Final Fantasy VII, Angelo assumes the identity of the game's Big Bad, who is a one-winged angel. When Jim asks him how he can fly despite lacking a second wing, Angelo realizes he can't and plummets to the ground.
• In the parody comics Sergio Aragonés Massacres Marvel, during the Fantastic Four segment, the Thing is holding an impossibly large machine (which turns out to be a food dehydrator bought from Ron Popeil's infomercials) above his head... until Doctor Doom points it's impossible according to the laws of physics, prompting the Thing to crash through the floor.
• A comedic issue of What If? told a story about the Fantastic Four making it to the moon in their origin story. After Ben, Reed and Susan all manifest their powers, Johnny exclaims that he can feel his own body changing, like it's ready to burst into flame, but nothing is happening. Reed didactically explains that of course he can't ignite; everybody knows that there is no oxygen on the moon's surface. Reed then exclaims, "What am I saying?!", and all four of them drop dead due to lack of oxygen.

Comic Strips

• Disney Adventures: In one arc of comic The Hair Pair, the starring rodents are cornered by their nemesis, Maxwell Blowfish. The villainous fish has them cornered, until they question how he's breathing out of water. Immediately, Maxwell starts suffocating, allowing the two to escape.
• Garfield: In the early days of the comics before Garfield's Anthropomorphic Shift, two strips featured Garfield walking on his hind legs and Jon reminding him that cats don't do that. In one, Garfield immediately falls flat on his face. In the other, he decides to walk on his front paws instead.

Films — Animation

• In Looney Tunes: Back in Action, there's a moment where the protagonists are falling out of the sky in a spy car that is low on fuel. Mere feet before they hit the ground, everything comes to a stop, which Bugs Bunny handwaves as the car being out of gas. When Kate, who is shown to have no sense of understanding of Toon logic, points out that reality doesn't work like that, the car promptly crashes into the ground.
• In The Pirates! In an Adventure with Scientists, The Pirate Captain boards a ship only to find it's a ghost ship. Once he realizes the ship isn't solid, he falls right through it.

Literature

• Bunnicula: Harold the dog is fond of eating chocolate, cheese, and fudge. He is reminded in some books that these foods are poisonous to dogs, but he remarks that he is a fictional dog and thus can eat anything he wants.
• The Hitchhiker's Guide to the Galaxy: One book explains how to fly by throwing yourself on the ground and missing. One rule is never to listen to what people on the ground are saying, because they will invariably tell you this is impossible, which will cause you to fall. Arthur Dent finds out this is true, since he starts to fall out of the sky when he thinks about how impossible it is for him to fly.

Live-Action TV

• On Cheers, Coach got excited on started doing handstand pushups like in the old days. Sam reminded Coach that he never did handstand pushups, that was his teammate. Coach immediately fell down.
• The Dick Van Dyke Show: In "The Sam Pomerantz Scandals", Rob and Sam do a Laurel and Hardy impression. During the bit, Rob as Stan sits down on a non-existent chair...until Sam as Ollie tells him there's no chair, and he falls on the ground.
• An episode of Gilligan's Island has the title character manage to fly with fake wings. When Skipper points out this is impossible, Gilligan instantly crashes. Afterwards, he asks the Skipper why he had to tell him.

Puppet Shows

• In The Book of Pooh episode "Double Time", Rabbit somehow manages to fly up in the air to talk to Kessie (a bird). Eventually...
  Kessie: But... Rabbit? You can't fly.
  Rabbit: Oh my, I believe you're [falls] riiiiiggghhhtt...

Theatre

• In Finding Nemo: The Musical at Disney's Animal Kingdom, a pair of penguins are flying while discussing the recent happenings in the plot. One of them cuts off their discussion by realizing, "Hey wait a minute. We're penguins. We can't fly!" They both promptly fall to the ground while screaming.

Western Animation

• Animaniacs is a big fan of this.
  • In one Slappy episode, Slappy and Skippy are dealing with a dog named Stinkbomb. After climbing their tree, Stinkbomb follows them up. Leave Slappy to bring up one important fact that Stinkbomb forgot about. Dogs can't climb trees.
  • One instance of Buttons protecting Mindy has him following her up a tree. After she tells him that dogs can't actually climb, he immediately falls.
• In the Arthur episode "To Beat Or Not To Beat", Francine puts on a football helmet, flaps her arms, and flies in the air. And then...
  Arthur: Francine, stop it! You're going to get hurt! Kids can't fly!
  Francine: They can't?
  Arthur: No! It's impossible!
  Francine: Oh. (screams and falls into a pile of leaves)
  Arthur: Don't you hate it when you have to burst someone's bubble?
• In a bumper on The Beatles, Ringo is flapping his arms and flying around the room, which John says is impossible. When Ringo grasps hold of this revelation, he drops to the floor, landing on his head.
  Ringo: [to John] You and your education!
• Bump in the Night: In "Cold Turkey", Squishington is annoyed when he sees the frozen turkey flying even though he's very certain turkeys can't do that. It takes consulting an encyclopedia entry and furiously pointing out that the entry says so to get the turkey to stop flying.
• The Critic: When Franklin Sherman discovers that the pilot of his plane was a penguin (who has been drinking on the job), he remembers that penguins can't fly. The plane immediately goes into a tailspin.
• Garfield and Friends:
  • One episode has Garfield getting chased by a dog. At one point, the chase has them on the ceiling. During that moment, Garfield stops to ask if the dog has sharp claws. When the dog shakes his head, Garfield tells him that he can't be on the ceiling because of that causing the dog to fall.
    Garfield: Boy, with some people, you have to tell them everything.
  • Lampshaded during a U.S. Acres segment. Orson points out that, in the real world, if you stepped off a cliff, you'd fall into the chasm the exact moment your feet stepped into thin air — whereas, in a cartoon, if you do the same thing, "you don't fall until you realize you're falling".
• The Grim Adventures of Billy & Mandy: When Billy and his dad enter a metal competition, Billy's dad decides to make a flashy entrance by flying onto the stage. However, the moment Billy says "I didn't know you could fly," his dad immediately realizes what Billy is saying and falls.
• Jimmy Two-Shoes: In "Jimmy in the Big House", the animals in Lucius's prison all start to complain in unison about how they don't belong there, then shut up once Molotov reminds them that none of them know how to speak.
• Looney Tunes:
  • In the short "Birdy and the Beast", Tweety jumps off a tree to fly away from a hungry cat, and the cat jumps off the tree to fly after him. Of course, he plummets once he's aware of what he's doing.
    Tweety: Gee whiz, puddy tat, I didn't know you could fwy.
    Cat: [laughs] You didn't know I could fly. Heh-heh... FLY?!?!?!
  • Subverted in the Daffy/Porky cartoon "A Coy Decoy". Daffy is romancing a wind-up decoy female duck, which Porky says nothing could possibly come of it. Daffy and the decoy swim off followed by four baby decoy ducks.
    Fourth decoy: [to Porky] You and your education!
• The Moxy Show: In the one episode produced for The Moxy and Flea Show, Moxy is driving a car with Flea when the latter starts to talk about how it bothers him that dogs can't drive. It takes a while for Moxy to be thrown off by the realization that he's a dog driving a car.
• SpongeBob SquarePants:
  • This classic scene from "Life of Crime":
    SpongeBob: At least it's warm around the fire.
    Patrick: Hey, if we're underwater, how can there be a —
    [fire goes out]
  • Near the end of "I Had an Accident", SpongeBob is attacked by a gorilla. When the protagonist wonders how can there even be a gorilla under the sea, the shocked primate responds by mounting a random zebra and riding away in a panic.
  • The second "Mermaid Man and Barnacle Boy" episode shows the two heroes descending from their cave and landing into their invisible car. Though they sit motionlessly in the air for a while, Barnacle Boy soon realizes that the vehicle is not really under them, causing them to immediately fall to the ground.
  • In "House Sittin' for Sandy", SpongeBob spends a good part of the episode in Sandy's treedome without his helmet. It's only when Patrick shows up wearing his and SpongeBob inquires about it does Patrick remind him they can't breathe air and he starts choking.

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