One Piece Chapter 1, page 52-55: Romance Dawn

A sign reads: "Ten years later...". At the harbor, Makino and Mayor Woop Slap stand together. Makino smiles: "Well, he's finally setting out, eh, Mayor?" Woop Slap grumbles: "I'll miss that rascal. But if he does become a pirate, he'll bring shame to the village." Other villagers wave: "I never thought he'd really do it!" Out on the water, a now 17-year-old Luffy sits in a small rowboat, smiling: "It's a good day to set out to sea!

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...

Luffy throws his stretched arm forward with incredible force, shouting: "...PISTOL!!!

Luffy's stretched fist strikes the giant sea monster directly in the face with a massive, bone-shattering "WHACK!".