One Piece Chapter 1, page 24-25: Romance Dawn

As Luffy walks away, his arm stretches out to an impossible length with a loud "BWOING!". Shanks and the pirates gasp in absolute shock: "His arm's stretching!!! Does this mean... did he-- He couldn't have!" Lucky Roux runs over holding an open chest: "It's not here!! The Gum-Gum Fruit we took from that enemy ship!!!" Shanks grabs Luffy by the collar and shakes him: "Luffy! You didn't eat that fruit, did you!?" Luffy, sweating, replies: "Yeah... I ate it for dessert!! It didn't taste all that great, though...

Shanks screams in panic: "That was the Gum-Gum Fruit!! The Fruit of the Devil, it's one of the secret treasures of the sea! If you eat it, your entire body becomes like rubber! And you will never be able to swim for the rest of your life!" Luffy's jaw drops in horror: "Whaaaaaaaaaat!? Aargh!!" Shanks yells: "You idiot!!!!" The scene then cuts to Luffy walking through the village, greeting the local fishmonger.