Big Jigglypuff
Play the Bridge Of Eldin stage with Jigglypuff. Break the Smash Ball, and wait until the ground breaks. When the ground is ready to return, go between the gap and press B. When it returns, Jigglypuff should be huge.
To make Jigglypuff even bigger when she is already huge, have Yoshi eat her. She will get twice as large.