This is when for some reason a character is chased by a large handful of other characters. In animated shows this can often have a freeze frame shot. Sometimes a show even ends an episode on this.
Has a high probability of being scored to Yakkety Sax.
A Super Trope to Thundering Herd.
Compare Chased by Angry Natives, while this trope is usually with named characters. Also compare Torches and Pitchforks, which may very well overlap with this.
This happened a lot at the end of the first series of Pokémon.
Happens in Mahou Sensei Negima! on occasion. One notable example occurs during Ako's Day in the Limelight micro-arc: Negi, thanks to the use of a time machine, ends up being chased by Madoka, two versions of Kotaro, Chachamaru and Chisame, and himself.
Recent events have taken this to the next (il)logical step, with the entire school after him.
In the Buster Keaton short film Cops he ends up getting chased by what looks like hundreds of cops.
In Love Potion No. 9, the female antagonist, figuring more is better, overdoses on the titular love-potion, which causes every man to hear her voice to fall in love with her, and every woman to hear her voice to hate her. And then she goes out in public...
At the end of Jingo, Commander Vimes was leading a procession and spotted an unlicensed thief stealing a lady's bag. He immediately gave chase while still leading the procession, which caused the people behind him to follow his lead since they didn't really know if this was how things were supposed to go, which caused the people behind them to run after them since they don't know what's happening at the front and they're getting left behind, which caused everyone watching to run after them too because, well, everyone else was doing it. While all of this was happening, the poor thief continued to run as fast as he could because he had taken one look over his shoulder and found the whole of Ankh-Morpork society bearing down on him.
Live Action TV
The Benny Hill Show would most likely be the Trope Codifier, as many, many of the skits ended up with someone being chased by an ever growing line of irate bystanders.
The Australian TV show The Farmer Wants a Wife.
This happens in Left 4 Dead if a Boomer vomits on you. Assuming, of course, you've got enough room to run and don't get immediately surrounded by the horde.
Sadly EA's games Rugby 06 and Rugby 08 often deteriorate into examples of this.
In Greg, Ted streaks across a college campus naked, as everyone chases him for disguising himself as a phony professor here.
In Freefall, Sam Starfall seems to seek out such episodes.
Happens on The Simpsons a couple times, most of which involve Homer and/or Bart (cf. "Bart vs. Australia," when everyone in the family is being chased by an array of living Australian stereotypes and characters — including a character from the movie Mad Max — because Bart refuses to get kicked in the butt as part of his punishment for prank-calling an Australian boy, "Guess Who's Coming to Criticize Dinner" when all the restaurateurs and chefs of Springfield chase after Homer after Lisa saves him from eating a dangerous eclair, "Saddlesore Galactica" where jockey-sized trolls chase after Homer after Homer breaks his promise to throw the horse race so they can win, and "Missionary Impossible" where PBS characters chase after Homer after he tricks them into thinking he's pledging $10,000 to the network).
The Family Guy episode "I Am Peter, Hear Me Roar" *
The episode where Peter goes to a women's retreat after getting in trouble for telling sexist jokes to a woman at work and becoming so in touch with his feminine side that he doesn't know what it's like to be masculine anymore
had Cleveland take Peter to The Million Man March, as Cleveland believes that being a man means learning respect and love for his own gender. Peter (who has been warped by feminism) believes that if men were more caring to women, society would be a better place and decides to get on the mike and let it be known. However, because Peter is a white guy angrily accusing all the men in the audience for causing society's ills and the fact that the audience consists of militant black men, this leads to this trope and Mistaken for Racist in the form of an overhead shot of Peter getting chased by everyone at the Million Man March.
Happens to the titular heroes in Teen Titans: Trouble in Tokyo, from three sources. Crazed Japanese schoolgirls were pursuing Beast Boy, Cyborg was hounded by sushi chefs, and Robin was chased by...the local authorities. Eventually, there was a mass convergence.