"YOU THINK THIS IS BIG??" you bellow, leaping off the stage and landing on the playing feild, making a huge dent "YOU AIN'T SEEN NOTHING YET!!"*
You're curious to find out how big you can get, and you have an audience. You concentrate hard on getting bigger and bigger, rising to 15, then 20 feet. Your own huge bare feet grow even larger in proportion to carry your bulk.
In the stands there is a rush ror the exits, but the fleeing crowd causes a bottleneck, and most of the crowd are trapped in the stadium, forced to watch your growing bulk getting bigger and bigger. You rise to 30, 35, 40 feet tall...and then...
(*Nobody is going to correct you on double negatives, are they?)