One Piece Chapter 2, page 11-12: THEY CALL HIM "STRAW HAT LUFFY"

Luffy smiles broadly and declares, "WELL YA SEE... I'M GONNA BE THE KING OF THE PIRATES!!!" Koby is completely dumbfounded, screaming, "K-KING OF THE PIRATES!!!? BUT... YOU'D HAVE TO MAKE THE WHOLE WORLD KNEEL TO YOU!!! WEALTH, FAME, POWER-- YOU'D HAVE TO ACHIEVE IT ALL!!! DON'T TELL ME YOU'RE AFTER GOLD ROGER'S LOST TREASURE, 'ONE PIECE'!!!!!

Koby continues to panic, shouting, "DO YOU WANT TO DIE!? EVERY PIRATE IN THE WORLD IS AFTER THAT!!" Luffy calmly replies, "AND SO AM I." Koby screams, "BUT THE ODDS AGAINST YOU ARE ASTRONOMICAL!!? YOU WANT TO BE THE KING OF THE PIRATES IN THE GOLDEN AGE OF PIRACY!? IT'LL NEVER HAPPEN!! IT'S IMPOSSIBLE!!" Suddenly, Luffy punches Koby on the head with a loud "KLONK". Koby rubs his head, crying, "HEY! W-WHY'D YOU HIT ME!?" Luffy simply says, "YOU WERE HYSTERICAL." Koby grumbles, "OKAY, I'M USED TO IT." Luffy smiles and says, "I'M NOT AFRAID TO DIE, KOBY! I'VE SET MYSELF TO BECOME THE KING OF THE PIRATES... AND IF I DIE TRYING... THEN AT LEAST I TRIED!" Koby is deeply struck by Luffy's words, thinking, "WHAT GUTS... WHAT DETERMINATION!! Y-YOU'RE NOT EVEN AFRAID TO DIE!?