Episode 17

"The Martial Arts Tournament" is the seventeenth episode of the One-Punch Man anime series and fifth episode of season two.

Summary
Metal Knight attempt to battle Elder Centipede, but fails to make even a scratch. After a lengthy battle Garou seemingly beats Metal Bat, but grudgingly admits that Metal Bat would have won if he hit him once. Metal Bat gets up and nearly kills Garou when Garou's back was turned, but stops when his younger sister, Zenko, finds him. Garou counter attacks, and is about to hit Metal Bat when Zenko gets between them and orders them to stop fighting. Garou relents (having a soft spot for kids) and walks away to find Watchdog Man. Metal Bat collapses due to too much damage from his battles with Elder Centipede and Garou. The two C Class heroes (Pineapple and Mohican) who have Narinki and Waganma are confronted by Rhino Wrestler and swiftly defeated, which causes the monsters to capture Waganma. Two Monsters named Phoenix Man and Sludge Jellyfish try to persuade Garou to join the Monster Association, but Garou refuses. Phoenix Man promises Garou that they will meet again if Garou will continue to hunt for heroes, and tells Elder Centipede and the rest of the monsters to retreat, with Metal Knight following them. Bang and Bomb are trying to find Garou, and Bang lets out his frustration on a monster name Boxing Demon, killing him violently. Many monsters of different disaster levels (Martial Gorilla, Do-S, Hundred Eyes Octopus, Pure-Blood, and Make Plasma) start attacking heroes, which worries the Hero Association. Before Do-S could kill Dynamite Man (her power being that if she whips someone, they will be under her control) with her mind controlled heroes, Fubuki stops her attack. Meanwhile in the Fight Tournament where Saitama is introduced to Bakuman, Suriyu, Lightning Max, Ring Ring, Hamukichi, Choze, Zakkos and Snek with Genos in the crowd. Suriyu notices Bakuman's bloodlust toward him, and is only after the prize money, although Suriyu wished he could have fought against WolfMan (Garou at the time). After Lightning Max defeats Ring Ring, Zakkos reveals that the fighters are often paired up based on their looks. Saitama deduces that Zakkos is weak since he's paired up with Saitama (Saitama being sorted due to him appearing "weak.") which angers Zakkos. In the post credits, Saitama slaps Zakkos in one hit, winning the battle much to Saitama's annoyance. Suriyu notices Saitama's strength and is excited that he will face Saitama in the finals.