You Got Your Exposition in My Argument

A main character, likely the Narrator, walks into a heated argument between at least two lower-downs. They both turn to the hapless bystander, trying to get support in the spat by yelling over each other. Expect something along the lines of, "Slow down and tell me what happened, one at a time," followed by two (or more) chunks of exposition. These will always conflict greatly.

In visual media, will often be accompanied by flashbacks from the perspective of each. Particularly in animated works, these may make use of completely different art styles to exaggerate the schism between the two versions of past events.

Note that this is only an expodump when the bystander (and thus the audience) is unaware of what caused the argument, and when it is a setup rather than the main plot. The "exposition" is also the important part of this trope.

Live-Action TV

 * A Drake and Josh episode had the title characters restart a feud over a foam finger. They reveal that as kids, Drake was the kid who got the last foam finger at a sporting event, leading to them having a fistfight in the lobby. Thing is Drake claims that Josh was being a brat about not getting it and hit him, while Josh claimed that Drake was Evil Gloating and hit him. To stop the two from fighting, Megan convinces a janitor to come and reveal what really happened: Drake and Josh were civil towards each other, with Drake being genuinely apologetic that Josh didn't get the foam finger. Megan, who was a toddler, tossed her candy at them from her stroller and started the fight. This stops the feud, but a new one starts when Drake and Josh argue who gets a new piece of merchandise that the janitor brought.
 * One I Love Lucy episode, "The Courtroom" had the Mertzes and Ricardos in court owing to Ricky accidentally breaking the Mertzes's new television while setting it up as an anniversary present, and Fred kicking in the screen of the Ricardos' television in a fit of rage. Ricky coaches Lucy to say that Fred was the one who ripped off the backboard before kicking in the screen -- which is half-true-- while Fred coaches Ethel to say that Ricky hacked at their new television with an axe and "pushed" Fred's foot through the television -- and that is Blatant Lies. The judge realizes they're both lying and asks them to recreate what happened with two television sets in court. They can't, so he tells them to settle it or he'll throw the book at both parties for perjury.

Video Games

 * In JumpStart Adventures 3rd Grade: Mystery Mountain: Bottley comes to the player character asking for help. Bottley hails from Professor Spark's mountain lab, which is self-sufficient and populated by robots. He explains that Dr. Sparks's Bratty Half-Pint daughter and Teen Genius prodigy Polly came home in a rage, before sending all of the robots back in time and changing history. When he takes you to the mountain, Polly explains what happened was that she had a big history test and made up goofy answers; her teacher, rather than laughing, gave her a "big fat 0". So Polly sent the robots back in time to ensure her joke answers were right. Of course, as Bottley points out, that is still super selfish.

Western Animation

 * American Dragon: Jake Long has this scenario as part of Jake's dragon training in "The Hunted". Lao-Shi brings him to settle a feud between two sprite tribes over a magical apple. One tribe claims that the apple was planted on their land, while the other says that the apple hung over their territory. Jake tries to settle it by asking why not cut the apple, only for them to scream over him because cutting the apple takes away its magical powers. Lao-Shi has to solve the feud by eating the apple, pointing out that when everyone argues, no one wins.
 * Arthur had this played straight in "Arthur's Family Feud". David's souffle gets ruined thanks to the kids horsing around in the kitchen just as he's about to take them to the arcade. As a result, he and Jane confront Arthur and D.W. about who is to blame. Arthur uses drawings to show that from his perspective, D.W. ran into the table. D.W. uses her toys, a princess doll for herself and Mary Moo Cow for Pal, to explain that Arthur knocked her into the table. Then Jane looks under the table; she realizes neither of the kids are wearing their shoes. Both Arthur and D.W.'s versions were true; they both slipped in the kitchen, D.W. bumped into the table first, and Arthur slipped and knocked her as well. It was a genuine accident. Out of guilt, however, the kids decide to try and recreate the souffle rather than go to the arcade, and their dad helps them when he cottons onto what they're doing.

Real Life

 * This is why eyewitness testimony is considered unreliable; as books like The Invisible Gorilla chronicle, it is very easy for two people to see the same event and have conflicting stories.