Ok Im going to make this easy,short,and simple for you to understand.To do this glitch, you must be jigglypuff and you must be at the Castle of Eldin(I know it's spelled wrong).You must also have to have jigglypuff holding the power to use its special move.Now when the knight comes riding on its stallion and lays the bomb,STAY AWAY FROM IT and let it explode so that there is a huge space for someone to fall through.Then wait a couple of seconds until you see a black portal in the sky.When the port starts rebuilding the bridge,with jigglypuff's special,jump down into the hole.Then While in mid-air use jigglypuff's growing special right before the portal restores the bridge.The bridge should restore while your giant,and pop you up.Once you get pop-ed up,you'll notice that jiggly puff is still giant.You'll be able to fight while your jigglypuff is giant until it dies and/or gets KO'd and returns on the plate.This is glitch can happen anytime on that stage,depending on the knight who lays the bomb.Note:this took me almost 2 weeks to finally master this glitch,hope you enjoy it.