It started out with a simple premise. Youtuber MasterofHyrule was making a video detailing every enemy and item that could come out of a pipe in Super Mario Maker. And then he took it up a notch.
MasterofHyrule displayed in his video every single enemy and item in the entire game.
The video serves to illustrate the absolutely crazy possibilities for creativity in Super Mario Maker, with screens containing extremely high enemy numbers or multiple Bowsers of varying size.
With Super Mario Maker having just come out, most gamers are still trying to figure out all the ins and outs of the level editor. Super Mario Maker gives the player no shortage of options in the design department, and its easy to see that players are taking advantage of that.