One Piece Chapter 15, page 16-18: Chapter 15: GONG

As the Buggy Ball flies directly toward him, Luffy prepares his defense. He inhales deeply with a "HUFF" sound and calls out, "GUM-GUM... BALLOON!!!" His body inflates into a giant, round rubber balloon, absorbing the impact of the cannonball right in his stomach.

Luffy's rubber body stretches under the force of the Buggy Ball, making a "GGNNN...!!" sound. Buggy is flabbergasted, stammering, "WHAT THE HECK IS THAT GUY?!" Cabaji and the animal-eared man watch in disbelief as Cabaji notes, "HE TOOK A DIRECT HIT FROM A BUGGY BALL!" With a loud "BOINNG!!" and "WOOOO" sound, Luffy bounces the cannonball right back toward Buggy's tower. Nami gasps, "AND HE BOUNCED IT BACK!" Zoro remarks, "YOU COULD HAVE AT LEAST TOLD US WHAT YOU WERE PLANNING...

The bounced Buggy Ball hits Buggy's pub directly, causing a massive explosion with a loud "AAARRRGGGH!!!" and "KA-BOOM!!!!" sound. Luffy smiles triumphantly and says, "THAT EVENS THE ODDS A LITTLE! LET'S GET 'EM!" Zoro smiles, saying, "MADE ME WORRY FOR NOTHING..." Nami stares at Luffy in utter disbelief, asking, "...WHAT ARE YOU!?