This is Photobomb is devoted to pictures and videos of people goofing it up in the background of events.
In the last couple of years, photobombing has become a full-out fad. Most photobombs these days are not random happenstance, but generally orchestrated by the photobomber. The 2014 Oscars ceremony raised photobombing to an art form, with respected actors like Benedict Cumberbatch, Kevin Spacey, Anne Hathaway and Jared Leto all getting in on the act.
This is largely the point of the Brazilian Tenso meme — to zoom in on a bizarre event/face buried in the picture that would probably not have been noticed otherwise.
This happens to everyone. People are always doing stuff that most people don't have the context to, so you could see someone doing something weird or nonsensical to you, but it could make perfect sense to the person performing said action. Just go to a comic con, for example, and you find a lot of people doing unusual things or wearing unusual clothing.
There was an infamous interview that is often shown on British outtake compilations from the news once where a spokesperson was discussing how the stretch of motorway he was on was quite safe... while behind him several cars crashed.
There is a gif of a couple clips from a newscast that plays this trope for laughs, especially given it was edited to where the background event is made hilarious.
In a study conducted by the American researcher Daniel Simons, people were told to count the number of passes in a ball game. The real point was whether or not the subject would notice a person in a gorilla suit walking through the game - about 50% of people did not!
This Finnish live broadcast about vandalism is pure gold with some kids ruining it.
There is a famous You've Been Framed clip taking place on a pier were one guy is being filmed talking in the foreground...while in the background, a woman is attempting to put up her umbrella which results in her being carried away by the wind and into the water.
In another clip, a little girl is being filmed bouncing on a trampoline while in the background, a second little girl attempts to put a garbage bag in a wheely bin. The second girl ends up falling in the bin.
A staple of many news blooper compilation videos on YouTube.
A prime example occurs at 7:10 on this blooper compilation when a man is being interviewed, oblivious to the fact another man dressed as Captain Jack Sparrow is carrying on behind him.