One Piece Chapter 39, page 17: FOR WHOM THE BELL TOLLS

Back in the forest, Usopp fires his slingshot, shouting, "SPECIAL TECHNIQUE 'KAYAKU-BOSHI'!! (GUNPOWDER STAR)" Jango is completely shocked ("!") as the explosive projectile flies straight toward him. The gunpowder star hits Jango directly in the face, triggering a massive explosion (SFX: KABOOM!! / SFX: BUAA-AAAAHH!!!!).