One Piece Chapter 1, page 53: Romance Dawn

Suddenly, the giant sea monster, the Lord of the Coast, bursts from the water right next to Luffy's boat. Luffy looks up, completely calm and smiling: "Our local sea monster! Sorry I have to do this... But here's an attack I've been perfecting since the last time we met!!" Luffy winds up his arm, stretching it backward: "Gum-Gum..."