After hearing rumors about a potential monster disaster, the Hero Association sends Golden Ball and Spring Mustachio to investigate Z-City. Kombu Infinity also hears these rumors and decides to check it out.
Golden Ball sees Kombu Infinity and attacks it with one of his special bullets, but the monster deflects it. Kombu Infinity grabs Golden Ball with its tentacles and smashes the hero into a wall, defeating him. Kombu Infinity then attacks Spring Mustachio, but the hero manages to parry the attacks. He then counterattacks with his Tomboy attack, but only manages to penetrate a single Kombu tentacle. Realizing that he cannot beat Kombu Infinity on his own, he calls for reinforcements. The scene then fast-forwards to a wounded Spring Mustachio collapsing and a victorious Kombu Infinity.
After the fight, Kombu Infinity spots Saitama and tries to attack him. While what exactly happened during their fight is unknown, Saitama punched a hole in a building and stole all of Kombu Infinity's hair to make kombu soup.