Chapter 20

"Rumor" (噂, Uwasa, Tonari: 21 + 22) is the 20th chapter of the One-Punch Man manga series.

Part 1
Spring Mustachio and Golden Ball are assigned to investigate the outskirts of Z-City. They discuss how the number of monsters in the city has been steadily increasing over the years. At the Hero Association headquarters, the staff oversee all of the investigations. Q-City is revealed to be the most dangerous city because of the large number of monsters. However, Watchdog Man seems to have no problem dealing with the monsters. The reports from cities W-City, H-City, and D-City stated that they encountered no problems. These regular investigations started to try to prevent potential threats. The report from F-City stated that Sneck found Hammerhead and that he will do further investigations. The staff members mention that Z-City's number of monsters is extremely high compared to other cities'. While Spring Mustachio and Golden Ball were investigating the ghost town, they sensed something nearby. The A-Class heroes encounter Kombu Infinity.

Part 2
Golden Ball takes the initiative and attacks first. His bullet is effortlessly swatted away, and Kombu Infinity grabs Golden Ball through the pavement and into a building, ultimately knocking Golden Ball out. Afterwards, Kombu Infinity attacks Spring Mustachio, but Spring Mustachio is able to parry all of his attacks. Spring Mustachio then launches his Tomboy attack. Unfortunately, Kombu Infinity manages to dodge it. Spring Mustachio resorts to calling for backup. Kombu Infinity reveals that there has been a rumor that extremely strong monsters have been gathering in the outskirts of Z-City. Despite, coming to meet the rumored monsters, Kombu Infinity decided to give up on that goal and become the rumored monster himself. Heroes received Spring Mustachio's call for reinforcements, and Blue Fire decides to go. Spring Mustachio is eventually defeated, thus leaving Kombu Infinity with nothing to do. Kombu Infinity ends up changing his mind and decides to go to an inhabited part of town. Sadly for Kombu Infinity, he encounters Saitama before he can go anywhere and is defeated by Saitama. In an unknown location, some monsters talk to each other about the monsters that live in Z-City. A silhouette of the elite monsters is shown. Back at home, Saitama cooks Kombu soup. Luckily for Kombu Infinity, Saitama spared Kombu Infinity's life and only took his Kombu hair. Genos mentions that the rumor that eating its hair will not grow one's hair, and Saitama becomes enraged.

Chapter notes

 * This is the first manga original chapter.
 * This chapter opens and ends the Rumored Monster Arc.