The Desert Born Outlaws, Part 1 (砂漠で生まれたならず者 その① Sabaku de Umareta Narazumono Sono 1), originally Andre Boom Boom (アンドレ・ブンブーン Andore Bunbūn) in the WSJ release, is the fifteenth chapter of Steel Ball Run and the seven hundred sixty-seventh chapter of the JoJo's Bizarre Adventure manga.
A flashback details the story of Marco a young servant, whose family had been serving nobles for generations in a faraway country. His job was to wax his master's shoes. When his master was found guilty of conspiring against the King of his country, Marco was considered an accomplice as well, and sentenced to death.
Back to present day, Gyro and Johnny are camping 50 km away from the 2nd water point. Johnny gets the hang of the Spin and accidentally discovers documents in relation to Marco, which angers Gyro. They are approached by Andre Boom Boom, who requires help and claims to have been bitten by a Gila monster. The duo is suspicious, only throwing him some fire to cauterize himself when he extracts the venom. Andre seemingly dies, only having managed to cut himself. Gyro kicks the blood-stained knife away, and notices that his boot bears strange cuts. Johnny and Gyro see the rest of the Boom Boom family, Benjamin Boom Boom and L. A. Boom Boom ride toward them. Gyro tries to attack them, but he is interrupted when a sharp object emerges from his foot.