Given everything else in Smash Bros Brawl has been revealed on the internet, it's only fitting that a few unintentional quirks are spoiled, too. While you might argue/joke "that's not a bug, it's a feature," we're pretty sure this one is a bug.

Normally, Jigglypuff's final smash has him turn into a giant puff and push people off the stage, subsequently returning to normal size. Using the collapsed bridge, someone found a way to keep him permanently enlarged. You don't have to sit through the entire video, only the first minute or so is important.