Futurama: At the beginning of an episode, Fry entered the game show "Who Dares to be a Millionaire?" and the first question was about which instrument is used to hammer a nail. Option A: a hammer; Option B: a nail. Before Morbo had a chance to say what Option C was, Fry answered "nail". Near the episode's end, Fry tried to destroy an invention by hammering a nail on it... with another nail.
Near the beginning of the episode "The Six Million Dollar Mon," there is a seemingly throwaway joke about the spiciness of LaBarbara's cooking-and another one where Roberto tries to steal and eat her skin. At the end, Hermes is saved when Roberto tries to eat his skin and is killed by the spice.
In "How Hermes Requisitioned His Groove Back", we see an old man waiting in line at the Central Bureaucracy for his birth certificate. Cut to "Lethal Inspection", aired 10 years later, the old man finally gets to Central Bureaucracy, only to have a heart attack right there.
Megas XLR loves this trope. It occurs almost Once per Episode. In the pilot, for example, Coop misfires a missile, which strikes a PoPTV satellite. When the bad guys combine their Mechs into a ridiculously huge final robot and is about to crush the cast said satellite crashes into it.
Throughout the pilot episode, Eric keeps calling everyone he comes into a contact with "a dildo". During the beginning of the second act of the same episode, Eric yells for his mother, telling her that "Kitty's being a dildo!" Eric's mother delightfully responds with:
Eric's mother: Well, I know a certain kitty-kitty who's sleeping with mommy tonight!
In The Movie, the boys use the promise of punch and pie to get other kids to join La Résistance. Way later, in "Super Best Friends", a Blaintologist hands out pamphlets for the Blaintology cult during a David Blaine performance. Guess what the pamphlet promises?
In "Jared Has Aides", Cartman pretends to be Butters and gets his parents angry by swearing at them over the phone. Later at the end of the episode, Butters' parents come to beat the stuffing out of him. Butters later refers to this very incident in "AWESOM-O", including somehow-realized knowledge of the setup.
In "The Poor Kid", the Agnostic foster parents make an offhand mention of a giant reptilian bird. It shows up at the end of the episode to deliver some Karmic (In)Justice.
In "The Biggest Douche in the Universe" Stan insults John Edwards, telling him he nominates Edwards for biggest douche in the universe. Later in the episode, John Edwards is abducted by aliens... who whisk him away to the Biggest Douche in the Universe Awards Show.
In "Chef's Chocolate Salty Balls", upon learning that a film festival only screens independent movies, Cartman stands by his viewpoint that independent movies are about nothing else than "gay cowboys eating pudding". It seems as though this goes unheeded, as the first movie Stan and Wendy attend for their paper is about lesbians, but around twelve minutes in, there is a big gathering at the Bijou theater for what the director calls a "visionary new motion picture". Said visionary motion picture is about, and is titled, "Gay Cowboys Eating Pudding."
In "Stunning and Brave", PC Principal accuses Kyle of hating Caitlyn Jenner and compares him to Brett Favre when he unenthusiastically rubbed his hands together when she appeared at the ESPYs. Near the end, when Kyle is being applauded for finally giving in and saying that Jenner is a hero, the scene cuts to the actual live footage of Favre doing so.
In what is possibly a parody on the trope namer, "The Two Faces of Squidward" has a fish gain the ability to fly out of seeing handsome Squidward, and then proceed to lose his untied shoe. Later in the episode, the shoe falls through the roof of the Krusty Krab, causing SpongeBob to push Squidward into a pole to save him from being hit on the head with it.
"The Great Snail Race" has one. SpongeBob, who's training Gary, calls him a lady to "humiliate and demean him". Cut to Sandy, who says "I don't know why, but I think I'll kick SpongeBob's butt tomorrow.". The next day, at the end of the episode, Sandy comes out of nowhere, kicks SpongeBob off screen and yells "That's for yesterday SquarePants!".
In the beginning of "The Smoking Peanut", Mr. Krabs is seen abusing the concept of Free Day, taking everything he can. At the end of the episode, it's revealed that the oyster got upset because her pearl was stolen. Guess who stole it?
In "Sandy, SpongeBob, and the Worm", the people of Bikini Bottom are trying to find a solution for the giant worm that has been terrorizing the town. Patrick comes up the solution to take Bikini Bottom and push it somewhere else. Squidward comments that Patrick's plan would get them all killed. Cut to the end of the episode, where Sandy and SpongeBob trick the Giant Worm into falling into a canyon. Guess where the people of Bikini Bottom actually pushed the town?
A long one. In season 1 episode 6 "Nevermore", Dr. Light angers Raven, causing her to lose control to her dark side, growing in height and using shadow tentacles to drag Dr. Light under her cloak. When the other Titans snap Raven out of it, Dr. Light is uncovered from Raven's cloak, pale and shivering, muttering about the darkness, implying some psychological problems. Three seasons later, in season 4 episode 3 "Birthmark", the Teen Titans are fighting Dr. Light again. Just as they're at a stalemate, Raven appears behind Dr. Light, again grown in height and wielding shadow tentacles (though staying in control this time). Dr. Light immediately goes pale and asks to surrender.
While the Titans are wandering Tokyo in the movie, Raven is handed a pack of "Super Twinkle Donkey Gum" at a newsstand. At the end, she appears on a billboard as the brand's new mascot.
In the Garfield and Friends episode "Attack of the Mutant Guppies", Garfield & Nermal contend with mutant guppies, who they defeat by tricking them into stomping each other down a sewer hole. Said guppies then appear in a subsequent US Acres Quickie out of a well; after scaring that show's cast off, one guppy turns to his fellows and says "Come on, lets see if we can get a spot on the ''Muppet Babies" (which aired opposite the show on CBS at the time).
The Garfield SpecialGarfield Goes Hollywood has a roller-skating bear that Jon, Garfield, and Odie see as one of the acts when they enter Pet Search. Later, there is a man named Herbie who spent 18 years training his pigeons to tap-dance, but when he presents them, they immediately fly away...and, to add insult to injury, the roller-skating bear skates into the scene and knocks into him.
In the exact same special, when Jon happily says that there is only one more act after theirs, Garfield comments that with their luck, it would be a dog that plays five instruments at once. Take a guess what the last act of the show was. (Although, he got disqualified because he was actually a human in a dog suit.)
Ruby Gloom loves these. An early episode starts off with a game of hide and seek that is quickly forgotten as it becomes a murder-mystery. When the victim is finally found at the episode's end, it gets tagged by the seeker.
The first episode has a scene where Jenny is playing hacky sack and accidentally kicks her sack into space. Later, she gets an alert about an asteroid about to crash into Earth. Normally it's the sort of asteroid that just burns up in the atmosphere, but this one can make it through because its mass has been slightly increased...by a hacky sack.
Also in one episode, whilst auditioning for the cheerleader squad, Jenny accidentally throws a cheerleader up so high, she doesn't come down. At the end, after the Iris Out, said cheerleader falls onto the black screen and asks "What did I miss?".
In the episode "Replaceable You", while Homer is talking to Roz, a beach ball falls out of nowhere into screen and Homer hits it off screen. A scene or two later, when they are in another room and Roz is meeting Mr. Burns, it falls back on screen in the room they're in, and Burns hits it off screen.
During "24 Minutes", Bart makes a phone call that accidentally gets crossed with that of Jack Bauer, so he leaves him a prank call. At the end of the episode, Bauer arrives to arrest Bart for the call.
We get a triple-whammy in "Hello, Gutter, Hello Fadder." In the opening, Moleman is seen being hassled by a pushy New Yorker, and is seen as defenseless. When he reappears later in the episode, he is revealed to be the king of the Mole People, and about to use an earthquake machine. His CMOA and Pre Ass Kicking One Liner, "No one escapes from the Fortress of the Mole People", is immediately dashed, as the bungee cord both Homer and Otto were on rebounds and sends them back to the surface, to which Moleman dejectedly says "Well, except for that."
An extreme example in the episode "Ned N Edna's Special Blend" where a billboard in the opening sequence says "Sleazy Sam's, Remember That Name". At the very end of the episode, a store owned by Sleazy Sam is opened.
The Mary Poppins parody has the family's nanny, Sherri Bobbins, lose her umbrella to Grandpa Simpson at the end of the second act as he's last seen flying off with it. At the every end of the episode when she leaves them, she picks it up from an unconscious Grandpa, revealing that he crashed into the house sometime after that.
In "Lisa Goes Gaga", Lady Gaga's birds carry off Grandpa when she arrives at the train station. At the end of the episode we see them still carrying him through the air.
In "Beyond Blunderdome", Homer helps make a movie and suggests making the villain a dog. He explains that the viewers would suspect the dog if he had shifty eyes. Guess what appears at the very end of the episode?
"Sideshow Bob's Last Gleaming": Bob scoffs at the idea of the Springfield Air Show, disbelieving that anyone cares about "buzz-cut Alabamians spewing colored smoke from their whiz-jets to the strains of 'Rock You Like a Hurricane.'" Guess which song plays at the air show later in the episode?
Another one: "Homer's Enemy," Season Eight, Episode 23, introduced Frank "Grimey" Grimes. Homer believes Frank is his friend. Everything Homer does drives Frank mad with frustration and anger, ending with his death. Frank's tombstone features the nickname "Grimey," as Homer has accidentally convinced everyone Frank liked the nickname. Frank hated the name. Guess whose tombstone Homer kicks over during a tantrum in Season 15, Episode 2?
At the start of "Bart's Inner Child", Homer reads the classified ads and remarks that the Men's Shelter is throwing away their soiled mattresses before noticing the ad for Krusty's old trampoline. Upon picking up the trampoline and setting it up in the back garden, he reveals his fantasy for his own theme park consisting of the trampoline and various other pieces of junk including a maze made from mattresses. Milhouse exits the maze and remarks that it smells funny...
In "A Star is Burns", Jay Sherman demonstrates that he can belch louder than Homer. When Lisa asks how many Pulitzer Prize winners can do that, he responds, "Just me and Eudora Welty". In the next act, Krusty says he has a date with Eudora Welty and a loud belch is heard offscreen.
"Much Apu About Something" has three, all set up during the parade:
Bart starts a battle between the fire department and the police which has the fire department blast the police with foam. When the Quick 'N' Fresh catches fire, they're unable to put it out because they're out of foam. It's suggested they used it up during the parade.
The fight causes Wiggum to lose control of the police department's SWAT tank and crash into the Kwik-E-Mart. He comes mere inches from hitting Apu, but causes it to collapse anyway. After the Kwik-E-Mart is rebuilt, Wiggum crashes into it again because he was letting Ralph drive.
The parade also shows off a new statue of Jebediah Springfield which is incredibly lackluster. During the tag, Mayor Quimby has the statue destroyed. The act causes the SWAT tank to be destroyed by a ricochet.
In one very old cartoon staring Porky Pig, Porky is in the Navy onboard a battleship. The Commander is taking roll call after reveille, when the bugler sounds the mess call. The Commander shouts, "Last one in the mess hall is a softie!" Unfortunately, Porky stumbles and gets that dubious honor. During the rest of the cartoon, Porky saves the day by capturing an enemy sub; at the end, he is honored at an awards ceremony, and then the mess call is played again. The Commander says the same thing; this time it looks like Porky might make it there first, but he leaves his award behind and has to rush out to get it before going back.
Another Looney Tunes example is the classic Wile E. Coyote and the Road Runner short Stop, Look, and Hasten! One of Wile E Coyote's schemes to catch the road runner is to install a large metal wall in the middle of the road. The wall is underground until Wile E activates it, causing it to immediately spring up. Naturally the wall fails to activate at the crucial moment allowing Road Runner to run past and forcing Wile E to give chase. Several more failed attempts are made to capture the Road Runner. At the end of the episode Wile E eats some leg muscle vitamins, making him fast enough to match speed with the Road Runner. A short chase follows, ending with the Road Runner running right over the metal wall Wile E had previously set up, at which point the promptly springs up and Wile E Coyote runs face first into it.
In another Coyote cartoon, "Beep, Beep", the coyote rigs a glass of water with explosives, but the Road Runner holds up a sign that syays, "Road Runners can't read and don't drink." After a few gags, the Coyote attempts to catch the Road Runner on rocket-powered roller skates, but he falls to the ground. He then sees the glass of water and it explodes.
The Legend of Tarzan episode "New Wave" has Professor Porter climbing into a tree to have a heart-to-heart with Tarzan. After this conversation ends, Tarzan swings off and the Professor wonders how he'll get back down. At the end of the episode, night has fallen and we cut back to the Professor still in the tree.
Often common in various Pinky and the Brain shorts, typically as the means of Brain's plan failing out of control. In the first short, "Win Big", Pinky confounds Brain with his Ralph Kramden antics, which Brain ignores. Eventually getting onto the game show to win money to fund his plan to take over the world, he gets to the final round, upon which the question involves—Ralph Kramden. Brain loses. (The episode is a Shout-Out not only to The Honeymooners episode where this happens, but a Cheers episode that was inspired by The Honeymooners one, all with the same approach to the brick joke.)
A season 2 episode of Avatar: The Last Airbender involved Sokka losing his boomerang after getting ambushed. He spends the first portion of the episode depressed over it and then seemingly forgets about it until during the climax he's randomly united with it, excitedly yelling "Boomerang, you do always come back!"
In the same show, the episode "The Cave of Two Lovers" features the nomads singing the eponymous song:
Nomad: ..."a mountain divides them apart!"...and, uh, I forget the next part, but then it goes..."SECRET TUNNEL!..."
[half an episode later]
Same Nomad: Hey, I just remembered the rest of that song! "AND DIED..."
Made even funnier in that he remembers the part about death just as they're talking about possibly becoming lost in the cave forever.
In the season 1 episode "The Spirit World (Winter Solstice, Part I)", Sokka is kidnapped by a spirit and taken into to the spirit world. When Aang saves him at the end of the episode, Sokka remarks that he really needs to use the bathroom. In the season 3 episode "The Avatar and the Firelord", Aang's behavior during his spirit vision of Roku prompts Katara to ask if the spirit world has bathrooms...to which Sokka responds that he knows for a fact that it does not.
In the same episode, Iroh uses his smelly sandal as a track for Zuko, who, 2 and a half seasons later, uses it to track him with June's shirshu.
The first series had a Running Gag about a unbelievablyhapless cabbage vendor who gets his cart of cabbage destroyed everytime he encounters the main heroes, which keeps happening all across the world. Come The Legend of Korra, which takes place 70 years later, a businessman is arrested for assisting terrorists. The name of the guy's enterprise? Cabbage Corporation.
In "Swarm of the Century", one of the many instruments Pinkie Pie gathers is a trombone. It was NOT part of the parade Pinkie drove the Parasprites out of Ponyville with, but at the very end, when the ponies return to Ponyville and discover it's now in ruins, Pinkie plays the stock Losing Horns on it.
In "Ponyville Confidential", Sweetie Belle and Scootaloo are under the mistaken impression that the way they will use the school newspaper to get their cutie marks is by making arts and crafts out of the paper, and Scootaloo patches up a bird's nest with it. Later, when the CMCs become writers for the school newspaper, Scootaloo, desperate for a story, decides to go to the same birds nest to get a story, but falls out of the tree and ends up covered in mud.
In "Princess Twilight Sparkle - Part 1", During a flashback to a time over a thousand years prior, when the story of how Celestia and Luna first used the Elements of Harmony to petrify Discord is revealed to Twilight Sparkle, the draconequus can be seen casually snacking from a bag of seeds as he scoffs at the princesses claims to be able to defeat him. He makes a mess as he eats, spreading the seeds everywhere. In "Princess Twilight Sparkle - Part 2", Discord reveals that he is surprised the seeds took so long to germinate, and were the direct cause of the Everfree Forest invading Equestria, over a thousand years after he sowed the seeds, and right in front of the princesses even.
Discord sets up another one in "Three's A Crowd" when he feels weak and asks for a fainting couch. All the ponies immediately look at Rarity.
Speaking of running gags, in "P.P.O.V. Pony Point of View", there's a running gag where Twilight keeps preventing Spike from eating snacks meant for others all throughout the first and second acts. The episode ends withher handing him a sundae.
In "Parental Glidance", Scootaloo is visiting Rainbow Dash's parents as part of a school report on Rainbow Dash. For lunch she gets Rainbow Dash's favorite childhood meal, half of which she sticks in her scrapbook. At the end of the episode when she gives the report, her teacher knocks her grade down because "there was a moldy sandwich in your report."
In "Carnival Knowledge", Rocko and Heffer decide to spend a day at a carnival. Little do they know it's full of rigged games. One game finds him trying to flip a frog onto a lilypad; pissed off by the frog's big mouth, he accidentally knocks it into the sky, forcing him to quit the game. Later, Rocko rides a roller coaster that goes so high that it leaves Earth's atmosphere. Guess who he finds up there, still calling him a loser? Then, after the disastrous roller coaster ride ends, a frustrated and spent Rocko decides to head home after being fleeced at every turn. Suddenly, there's a loud WHOOSH!, and the frog sails back down to Earth, landing perfectly on one of the lilypads. Shocked that someone finally beat one of his rigged games, the carnival's owner reluctantly gives Rocko a prize.
In "Who Gives A Buck?", Rocko and Heffer have difficulty finding a parking spot at the mall, and end up following a guy who turns out to be a little kid who's spent years trying to find his mom's car. Later in the episode they finally find a parking spot, and on their way to the mall pass a little old lady who mutters "Son? Have you found the car yet?!"
In "Teed Off", Heffer is seen goofing off at his job as a groundskeeper at the golf course by writing Crop Circles in the turf. At the end of the episode, a pair of aliens land in the golf course after dark to examine the crop circles, and one of them says "Who keep writing this stuff?!"
In the Christmas Episode, Ed Bighead is mad about not getting an invitation to Rocko's Christmas party, and Bev tries to assure him that the invitation probably got lost in the mail. At the end of the episode, the little elf shows up at Ed's doorstep with his invitation, which apparently really did get lost in the mail.
In an episode of Justice League, Deadman possesses Superman while he's telling Wonder Woman about a restaurant ("They have milkshakes so thick...*possess* I need your help!" "That IS thick.") At the end of the episode, when Deadman finally leaves, Supes picks up right where he left off ("...You need a spoon to eat them. (Beat) What am I doing in Africa?")
In the teaser to one episode of Aqua Teen Hunger Force, Steve makes fun of Dr. Weird by posing as him and shouting "Fill me with BBQ sauce because I'm dumb as hell!" A few episodes later...
In the episode "Pins, Spins and Fins! (Shark Story Cut for Time)", a man working at a bowling alley (high from huffing shoe spray) has a hallucination where one of the bowling balls tells him to burn down the local retirement home. At the very end of the episode, a newspaper headline reveals that 88 people died in the burning home because the fire department was busy saving an abandoned amusement park (which Donna accidentally set on fire).
In "The Men in Me", Justin Bieber concerts are described as being for "little white boys, white girls and a rainbow of pedophiles". At the very end of the episode, Cleveland and Junior attend a Bieber concert, and a caption reveals that it was part of the world's largest To Catch a Predator sting (Cleveland is currently awaiting trial).
In the episode "Lois Kills Stewie", when the family is tied up in rope, they decide to pass the time by starting a celebrity rumor. Peter suggests that Rob Schneider takes illegal immigrants from Home Depot and pays them to choke him in the shower. Later, it's shown to be apparently true.
Immigrant: Señor Rob Schneider, you must come and see this! Rob Schneider: I don't pay you to watch TV, now get in the damn shower!
In "Brian Sings and Swings", Peter, thinking Frank Sinatra Jr. is a bad influence on Brian, calls his "mother", Mia Farrow. She shows up at the end to give Frank a spanking.
In "When You Wish Upon A Weinstein", Peter worries about entering a synagogue with his Christian upbringing, with a group of nuns being alerted of such to illustrate the point. Then at the end, the Griffins seek refuge from an angry mob inside a bus. Guess who's in there waiting to whack Peter with rulers.
In "Trading Places", a cutaway gag shows Peter working as a police sketch job and making racist drawings (which got him fired). Later in the episode, when Chris gets off work and asks if his day can get any worse, he's promptly mugged by a man with Peter's drawing for a head.
In "Believe It or Not, Joe's Walking on Air", Cleveland states at the beginning that he hates shows that cut from the story to "some bullcrap". The scene then cuts to an image of Adolf Hitler riding a unicycle juggling. Later in the episode, Peter says that they have to "re-cripple" Joe (who during the episode had surgery to get new legs), and says it's the right thing to do, "like taking out Hitler". It then cuts back to the clip of Hitler riding the unicycle, but this time Peter runs in, knocks him off, and punches him in the face, stating to the viewer, "See? We had a plan for that all along".
In one of the longest brick jokes, in "To Love and Die in Dixie", Peter and Brian have painted the car to resemble the General Lee. When they try to jump in it, Brian just slams into the door and is knocked unconscious. Three years and a cancellation later in "The Fat Guy Strangler", during the standoff with Patrick, Peter is being held captive. Brian picks up a rock, throws it, it hits Peter in the head, and they have this exchange.
Peter: You missed! Brian: No I didn't. That's for rolling up the damn window when I tried to jump into the General Lee.
In "The Father, the Son and the Holy Fonz", we see couple coming from a fertility clinic and the husband tells his wife to image a baby boy floating past them in a bubble, only for Stewie to go past them rolling in a disinfectant bubble, which prompts the husband to tell her to imagine Lindsay Lohan doing a crabwalk naked. Later, Peter opens his door to see just that.
A different Brick Joke was done in the form of a deleted scene: Peter tries to get into Hinduism, but tackles the guy believing that the red dot on his forehead was from a sniper rifle. Later, the Hindu guy shows up with blood on his forehead, telling Peter "You were right!" before collapsing.
In "Peterotica", a man drives through the Kool-Aid Man's house, promoting him to remark that it's actually annoying from the other side of the wall. Later, when Carter throws Peter off a train, he too crashes into Kool-Aid's house just as he's finished plastering his wall.
In "Dog Gone", Brian is drunk in a pizzeria talking to the father fromFamily Circus. Brian gets mad and goes on a tirade about how all he ever does is judge other people, in the end telling him to "fuck your wife in the face", the father saying that he's going to do that exact thing. Later in the episode, Peter is reading a newspaper and comments on how shocking today's Family Circus is.
"Meg Stinks!" starts with the James Woods High School principal explaining College Day is where seniors go to choose where they get HPV. In the end, Meg says she got accepted into college and on her first night, she got HPV.
In "Farmer Guy", the Griffins' pictures are placed on a "Known Meth Distributors" poster alongside a live-action photo of Jodie Sweetin. At the end of the episode, we hear Sweetin knocking on Peter's door asking for some meth.
In "Tales of a Third Grade Nothing", when Angela mentions she recommended Peter for a promotion, Peter says that he had eaten a fortune cookie which said that an obvious lesbian would bring great news. He also mentions it said a grand piano would fall on him and then looks up to make sure he is safe. He then leaves the room as nothing falls on him, but one does a few minutes later.
At the beginning of the episode, Peter unintentionally sets fire to and blows up a children's hospital while attempting to destroy a competitor's billboard to impress Angela. At the end of the episode when Peter asks Angela if he is getting promoted she informs him that he will be going to jail for destroying the hospital.
In the episode "With Friends Like Steve's", Stan awakens to mentally insane teenager Barry holding a gun to him. When Stan asks where Francine is, it is revealed that she is buried alive in the back yard. At the end of the episode, Stan is driving Barry home and remarks to Steve, "I'm hungry, let's go dig up your mother do she can make us breakfast".
Even better: in the Season 1 episode "Roger Codger" (aired June 5, 2005), Roger is disguised as an elderly woman and meets Gertie, who he describes as "a nasty, old, racist sidekick"; at the end of the episode, when the FBI has the family cornered, they pull Gertie's wig off and pass her off as the escaped alien. Fast forward to February 20, 2011, and the Season 6 episode "You Debt Your Life" sees Roger and Stan going to Area 51: as they walk through the military base, they pass a tube that has an unconscious Gertie suspended in liquid.
Another example from the episode "Joint Custody": Roger and Stan are high and Roger purchases a large bag of cat food to anchor him because he believes he is "becoming immune to gravity" and that he will float away. At the end of the episode, Roger puts the bag down and does float away.
In the episode, "The Kidney Stays in the Picture", Roger spooks Steve by describing how a kidney is removed for transplant. Later in the episode, when he is removing another character's kidney (the man who had sex with Francine before she got married and may or may not be Hayley's real father), it matches his description exactly, right down to the song "Hip to be Square".
In "Live and Let Fry", we are treated to a cow literally jumping over the moon — only to drift uncontrollably into space. The final gag of the episode? The cow comes back. In a painful, fiery way.
In "Great Space Roaster" Steve mentions a nonsensical entry in Roger's diary reading "Million dollar idea: DiaRhea Perlman", two years later in "The Unbrave One" Roger mentions his terrible idea for a chain of Rhea Perlman themed restaurants called, wait for it, "DiaRhea Perlman's".
In "The Hand That Rocks the Mabel", Stan steals a clown painting from Bud Gleeful. Sixteen episodes later, in the season finale "Gideon Rises", the Gleeful Family takes over the Mystery Shack and Bud can be seen comfortably leaning on that exact clown painting.
In "Legend of the Gobblewonker", there's a flashback which shows Stan making the kids paint fake money (and end up in the county jail moments later), and Stan comments "You call that Ben Franklin? He looks like a woman!" Six episodes later in "Irrational Treasure", Dipper and Mabel find secret government documents and Mabel points out one revealing that Ben Franklin secretly was a woman.
In "The Love God", many of Mabel's past crushes appear in visions to her, including an unnamed boy seen briefly in the first episode whom she passed a note to asking if he liked her. Here, he enthusiastically ticks all three options on the note:
Near the start of "Evicted!", Finn shoos a worm off his bed. At the end of the episode, after Finn and Jake reclaim their tree house, they find dozens of the same type of worm crawling around the living room, and Finn says accusingly "Did you guys get on the bed?"
This is once again referenced in the Season 4 episode "King Worm", where it ends with resolving either the same situation, or a similar situation from the end of "Evicted!", kicking the King Worm out of their house.
Near the start of "The Other Tarts", Princess Bubblegum mentions that she needs to find a replacement for the Royal Tart-Toter, who's getting old and senile. The episode ends with the blind, deaf, and delirious Tart-Toter barging into the Back-Rubbing Ceremony and going into a pseudo-philosophical rant.
Code Lyoko: In the episode "Image Problem", Jérémie jokes about the scanners having negative health effects in reference to Yumi/XANA being devitalized before she can tell the group what happened. Some 15 episodes later, XANA impersonating Franz Hopper "confirms" that the scanners have a negative effect.
(Blooper) Bunny, a 1991 Bugs Bunny cartoon, shows a brief dance clip with Bugs, Daffy, Elmer and Yosemite Sam. Then we see several outtakes of the dance routine. In one, Bugs stops suddenly, shouting, "Hold it, Doc! There's a loose floorboard." Later, after Elmer tries to shoot Bugs and Daffy with a real rifle instead of his prop gun, Daffy goes ballistic on Elmer (with Bugs trying to get the camera to cut). Daffy proceeds to storm off after telling Elmer, "Expect to hear from my attorneys about this unfortunate incident." He then steps on the loose floorboard, which whacks him in the face.
In the Wallace & Gromit short "A Grand Day Out", Wallace tests the moon's gravity by kicking a ball into the air, but it doesn't come down and floats through space. At the very end of the credits, we see the ball still floating through space.
In the VeggieTales episode, "Josh and the Big Wall", Bob the Tomato states that Larry is too exhausted to participate on the show, so he decided to let him sleep in. Guess who appears at the very end of the episode, in his pajamas from the Christmas Silly Song?
Larry: Hey, is it time for the show? [Cue the lights in the room being shut off]
American Dragon: Jake Long: At the beginning of "Bring It On", Professor Rotwood was escorting students through the museum when he accidentally broke a statue. He quickly told the students they saw nothing. Neither him nor the incident have been mentioned again until the end credits, when he phoned his mother for bail money because he was arrested for it.
Brier Beauty of Ever After High jumping out a window on a whim is already pretty funny. Prince Daring catching her, because it's "kind of (his) thing" is hilarious.
In an episode of King of the Hill, Hank tries to flush his late father's ashes down a bar's toilet, but he can't because the owner says every time someone flushes ashes down the toilet, he always has to pay the plumbing bill. Later, when they succeed in doing so, Hank gets the bill in the mail the next day.
At the end of the pilot episode, "The Looney Beginning", Buster and Babs complain to the cartoonist asking him to give them a "Created by" credit. The Credits Gag at the end was "Created by Buster and Babs".
Early in "Hollywood Plucky", Buster and Babs are sitting at an abandoned bus stop in the middle of nowhere, due to faulty directions Plucky gave them. At the very end of the episode, after Plucky finally makes contact with Cooper DeVille, Cooper mentions that he already made the script that Plucky was pitching, only starring Buster and Babs. He found them at a bus stop while out driving.
In the short, "Jungle Bungle" from the episode, "Pollution Solution", when Acme Acres is being flooded due to global warming, Buster asks to book a reservation on Noah's Ark. In Steven Spielberg's next animated series, Animaniacs, in the cartoon, "Noah's Lark", Buster and Babs make cameo appearances as the rabbits that board Noah's ark.
At the beginning of "Hog Wild Hamton", a commercial for the Acme Clearinghouse sweepstakes airs, featuring people who have won enough money to buy a new house. Hamton enters the sweepstakes only for the subscriptions to magazines that appeal to his interests. At the end of the episode, Hamton wins the sweepstakes, and a new house to replace the one that got destroyed as the result of Plucky throwing a Wild Teen Party behind Hamton's back.
The Goofy cartoon "Teachers Are People" has Goofy forcing an unruly student to hand in his various weapons, including a ticking hand grenade, which Goofy puts in a bucket of water. At the very end of the short, the grenade finally goes off.
In the pilot episode of Goof Troop, P.J. and Pistol make a bet to see whether their father will bust a gut or a spleen when he sees the dent the Goofs made to his boat. Later, when Pete has a Freak Out after seeing the dent, P.J. gives Pistol a quarter from the bet.
Bounty Hamster. Lampshaded in "The Good, the Bad, and the Adorable". A group of cute critters accidentally take off on a huge rocket engine and fly around the entire planet returning just in time to run over the Big Bad at the crucial moment, whereupon Marion pops up and says, "Bet you forgot about those guys, huh?"
In Barbie in a Mermaid Tale 2, the lead Stargazer vows revenge on Eris despite his shrunken size and slower swimming speed. It takes him the rest of the movie to get there, but he does so at a crucial moment to bite her nose.
When Static goes to Africa, he gets excited about seeing tigers but his father tells him there are no tigers in Africa. The villain of the episode is a leopard. In a later episode, the same villain shows up and Gear calls him a tiger because he has stripes instead of spots. At which point Anansi comments, "I too have often wondered about the stripes."
The recurring joke about having a treehouse instead of a gas station as a base.
In an episode of Dexter's Laboratory, Dee-Dee torments Dexter by using a label-maker to claim stuff as her property. At one point, she labels the toilet as hers, leaving Dexter with no choice but to go on the living room floor. At the end, after the parents send Dexter to his room (It's a Long Story), they wonder why the floor's wet.
In a season 2 episode of Archer, Archer, annoyed with his valet Woodhouse, threatens to punish him by making him eat a big bowl of spider webs. However, the episode ends with him never carrying out that threat. Jump ahead to season 4, where Woodhouse leaves Archer stranded in Montreal; when Archer finally returns home and is pissed off, guess what Woodhouse's punishment is?
Archer: Woodhouse! I'm gonna check that bowl!
One episode of Scooby-Doo took place in a candy factory. At one point, the villain tries to trap Scooby and Shaggy by pouring a layer of taffy on the floor. Scooby manages to free himself, but Shaggy is forced to remove his shoes to escape. After the villain is captured, Shaggy and Scooby celebrate by eating the taffy. Scooby ends up eating Shaggy's shoes as well.
Penn Zero: Part-Time Hero: One gag in "Baby-Pocalypse" has Sashi throwing a spear at a presumably non-sentient rubber duck, puncturing it and causing it to sink. Several scenes later the team visits a local hospital to get Penn's arm re-attached to his body and Sashi ends up sitting next to the very same duck, who is now wrapped in bandages and glaring at her.
Johnny Bravo: In the first Christmas episode, Johnny mistakes Santa Claus for a burglar and breaks his arm. He is forced to take over Santa's job for the night and does surprisingly well, but Santa leaves warning him that he's still mad. In the second Christmas episode that aired almost five years later, when Johnny meets Santa again, Santa suddenly punches him out and says they're finally even.
The Adventures of Jimmy Neutron: Boy Genius: In "Maternotron Knows Best", Jimmy's robot duplicate of his mother makes Carl and Sheen fill out a long series of application forms to prove that they're really friends of Jimmy. We don't see them again until the very end of the episode, where they've been filling out the forms well into the night.
In Golan The Insatiable, towards the end of the first third of the episode "Golan the Impregnable", Golan gets wasted by drinking a whole keg and tossing it into the sky so high we don't see it come down. Towards the very end of the episode, the keg comes falling down and crushes Keith, putting him in a coma. Ironically, this is exactly what Dylan was trying to do with the croquet mallet before Keith tricked her into putting it down and then tried to hit her with a rock when she was off guard. By the time it falls, its presence was likely forgotten as no attention was given to the act when Golan tossed it.
In the Steven Universe episode "Catch and Release", the Gems are deciding what to do with with a de-powered and smaller Peridot, who is holed up in Steven's bathroom. When he states displeasure (because he has to use the bathroom every day), Pearl jokingly states that the only other option would be to keep Peridot outside on a leash, and then immediately starts genuinely considering the idea. Exactly three episodes later, after Peridot shoots her mouth off to Garnet about being fused, Garnet puts her on a child leash, with harness, and ties her to a fence like a misbehaving dog.
In the episode "Ocean Gem", after Lapis Lazuli gave thanks to Steven, he replied "No prob, Bob." Unfamiliar with the term, she replied "... It's Lapis." Fifty-seven episodes later, when Lapis was posing as a human in the episode "Hit the Diamond", she went by the alias of Bob.
In Jackie Chan Adventures episode Viva Las Jackies, animal tamers Helmut & Ulf (parodies of Siegfried & Roy) mention that they are tired of training tigers and instead will have auditions for a juggling bear. By the episode Monkey a Go-Go, they have found their bear.
In the BoJack Horseman episode "After the Party", Wanda tells BoJack a similar joke based on the original brick joke.
In the Rugrats episode "Party Animals", during a costume party at Drew's house, the babies get chased by a partygoer dressed as a baby, who is asking them to pull his finger, before managing to trap him in the bathroom. At the end, after Angelica convinces the babies that everything they saw tonight wasn't real, she opens the bathroom door and is greeted by the man shouting "Hey, pull my finger!".
In Beast Wars, one episode of the first season has Rattrap ask Optimus Primal if he died, could he have his quarters. Primal dies at the end of the season and spends the first few episodes of the second in that same position. When he finally comes back and saves the other Maximals from the Predacons, Primal declares the first thing he's going to do is get Rattrap's junk out of his quarters.
In the Star vs. the Forces of Evil episode "Starcrushed", Oskar accidentally sends his keytar flying into the sky and wonders if it will fly to Mars. During the Silent Credits, it lands on the Diaz house's porch.
At the start of the theme song, Mr. Cat crushes a flower with a mallet causing Kaeloo to get angry. At the end of the song, she finds him and beats him up for it.
In the middle of the episode "Let's Play Golf", Kaeloo mentions something about pennyloafers coming back in style. At the end of the episode, Mr. Cat asks her if pennyloafers are really coming back in style.