Yeah YTP is what I think of when I think of YouTube-originated art form. It's sort of like a visual version of the "Paul's Boutique" crazy sampling to make new art.
Absolutely true - it's actually crazy how much of an art form YTP became. (Not sure how popular it is these days?). It was a whole style with its own conventions, memes, etc. And on the surface, it seems really stupid, but there's a lot of creativity and talent that went into those wild videos.
This one is an old favorite of mine: https://www.youtube.com/watch?v=PTdxPliBdZs
Also, the "Wow, It's Made" series: https://www.youtube.com/watch?v=dMapmlUwerw