One Piece Chapter 39, page 16-18: FOR WHOM THE BELL TOLLS

Luffy glares at the cheering pirates and yells, "I DON'T NEED YOUR CHEERS! I'M GONNA BEAT YOU ALL UP TOO, SO BE READY!" The pirates scream in terror ("GYAAAA-AAAHH!!!"). Kuro, sweating profusely, stares at Luffy in disbelief, thinking, "How can it be... My plan... MY PLAN... CANNOT FAIL!!" Luffy prepares his final strike, chanting, "GOMU GOMU...

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!!!!).

On the slope, Luffy snaps his head forward with incredible force, completing his attack: "...BELL!" (Gomu Gomu no Kane). His forehead slams directly into Kuro's face with a devastating impact (SFX: DO-GAAAN!!!). Kuro's glasses shatter instantly as he takes the full force of the headbutt, his eyes wide with shock and pain ("!!!?").