A group of people are walking in a straight line. Suddenly, the person at (or near) the front of the line stops walking for whatever reason. This causes everyone behind the person to bump into one another. This gag is mostly seen in Western Animation.
Compare Cliff Stack.
- Princess Princess: The three princesses have been on the stage and are leaving it for a scene change. Mikoto is at front but suddenly stops which cause Tohru and Yuujirou to bump into him and another. The reason to stop: outside the stage waits Mikotos sister and girlfriend, the last two persons he want to see him in girl's clothes and who he actually have asked to go home to prevent it. Mikoto then blacks out.
- Ghost in the Shell: Stand Alone Complex episode "Ag2O". While the Tachikomas are rolling along a corridor the one in front stops to speak to Batou and the others run into it.
- If The Three Stooges never used this, they'd miss the boat.
- Happens in the Fellowship of the Ring film, when the Hobbits are running away from Farmer Maggot.
- Disney films
- Snow White and the Seven Dwarfs. This happens to the dwarfs while they're marching along. This example is referenced in Psychoville, where the dwarfs are told when they go on stage and see Snow White for the first time, they stop and tumble over. It's supposed to prompt the audience to laugh.
- The Jungle Book. While the elephants are marching through the jungle the one in front stops and all of the rest ram into him. The scene was taken from a short called Goliath II. Also serves as an Early-Bird Cameo for the elephants in this film.
- The Sword in the Stone. Merlin uses his "Higitus Figitus" spell to put his belongings in a traveling bag. After a small jar cuts in line it stops the other items behind it from moving forward and they run into it.
- The hyenas in The Lion King did this. Bonus points for one of them getting bumped off the edge of a cliff into brambles as a result.
- Mulan: In the Training Montage, when the soldiers are jumping along some poles jutting upwards in a line, Chien Po falters and stops moving forward. Shang, coming behind him, defies the trope by stopping in a controlled manner before running into him, but that just makes the jam form behind him when everyone else fails to do the same.
- An American Tail: as the Mousekewitzes board the boat to America, Fievel keeps stopping to ask questions, causing the mice behind him to crash to a halt, eliciting cries of "Keep walking!"
- A Bug's Life when a falling leaf blocks the path.
- Mentioned in Jingo. Vimes, at the head of a procession, spaces out and begins slowing down and finally comes to a halt, and the entire procession does the same, with jostling and bumping for those slow to keep up with events.
- Seen in the Walt Disney Presents episode "Mars and Beyond", during the "typical science-fiction story" sketch, while the secretary is being pursued by the Martian leader and his minions. After she changes into her superhero costume, she holds up her hand to stop the leader and his minions slam into him.
- One episode of Ned's Declassified School Survival Guide had an episode partially centered around this, with Cookie broadcasting traffic updates through student's cell phones to avoid things like overturned AV Carts; meanwhile, Moze is trying to spend time with her boyfriend at his locker, but is diverted by a broken pipe, and a lot of the alternate routes she takes are suggested by Cookie, leading to her constantly getting trampled. And Ned was put in by Mr. Sweeney as the new Hall Monitor, and no one's listening to him. It all collides- quite literally, as Cookie's update makes a large crowd head up to the second floor, right into the "hall party" Ned was failing to contain; resulting in a huge pile-up of "overturned" students on the floor.
- Beetle Bailey: Sarge orders a group of men marching in a line to stop hurriedly, and they all "plong" into each other.
- The Magic School Bus of all places. Twice, in "In A Beehive". Wanda calls Tim out of stopping like that the second time it happens.
- Inverted on Danny Phantom. The girls in the pageant are all walking with books on their heads. Sam is at the back of the line reading hers, so she doesn't realize the line is moving at a different speed than she's walking; she bumps into the last girl in front of her and starts a chain reaction.
- Occurs in the second episode of My Little Pony: Friendship Is Magic, with Pinkie Pie in the lead and stopping abruptly when they encounter a roiling river, causing the others to bump into each other.
- A variation shows up in "Dragonshy," where Fluttershy slips while climbing down a rocky slope, sending her hurtling down into the other ponies in front of her, which sends them all down.
- Occurs in the twenty-fifth episode of Code Lyoko, with Jeremie in the front. Jim gets in front of him. He stops, then Yumi crashes into him, Ulrich crashes next, and Odd at the end. Comically, a brake screech sound effect is heard.
- Combined with Distracted by the Sexy on Futurama; In one episode, Leela gets plastic surgery to make it look like she has two eyes. While walking down the street, she ends up causing this trope to the Sons of Mom, who are Stooge expies.
- Happens in the Donald Duck cartoon "Good Scouts". Donald is leading his nephews on a hike. He orders a stop, but the last nephew is distracted and knocks the others over like dominoes.
- Karl von Clausewitz devoted a number of pages to the effects of traffic in military columns.