Pooh's Adventures is a genre of crossover fan videos, that typically, but not always, star the cast from Winnie The Pooh (hence the name). The genre involves taking clips from various sources, and editing them into one single video to make them look like they're interacting with each other. This genre dates back to the late 2000s, and the exact origin is unknown, but most people recite someone named Brerdaniel as the one who made it popular.

https://tvtropes.org/pmwiki/pmwiki.php/WebVideo/PoohsAdventures