One Piece Chapter 22, page 2: YOU ARE A RARE AND PRECIOUS ANIMAL TOO

Nami hands the mended straw hat back to Luffy, explaining that she simply stitched up the cuts and warns him not to poke it too much. Luffy enthusiastically thanks her, but immediately pokes a finger right through the fresh stitches. Realizing his mistake, he mutters, "Uh oh..." as Nami's face contorts in anger. She furiously stabs him in the face with her sewing needle, prompting Luffy to scream in pain. When Luffy protests, Nami points out that physical blows don't hurt his rubber body, so she has to use a needle. Luffy cheerfully agrees that this makes sense. Zoro wakes up, complaining about the noise, while Luffy loudly declares that he is hungry.