Episode 6

"The Terrifying City" is the sixth episode of the One-Punch Man anime series.

Summary
Saitama is busy lazing about and reading manga as Genos' studies his unorthodox training methods, sketching down his every move and antic. As The former pinches his brow in frustration contemplating how much of a pain it'll be to keep this charade of being his master going. The cyborg mentions his concern over his inactivity over the past few days stating that due to an overabundance of C-Class heroes, the association eventually strike those who are inactive for more than a week from their registry. Shocked and horrified by this revelation, Saitama sets out on patrol before the last day kicks in having already been inactive as a hero for six, wishing to accompany him Saitama rebuffs Genos' request stating to train himself in patience; though in reality Saitama just doesn't know how or in what way to instruct him spouting things off the top of his head.

Having been out on patrol for two whole peaceful days the hapless hero fidgets nervously as this is his last day to avoid getting laid off. As if to make matters worse Speed-o'-Sound Sonic shows up to settle their (imaginary) rivalry, only for Saitama to brush him off greatly provoking the ninja into attacking him only for the latter to bite his sword in half. Greatly bewildered by these events Sonic finds himself intimidated by the irked Saitama who threatens to hit him just as a bystander sitting next to a boisterous upper ranked hero; Tanktop Tiger who reproaches Saitama's crazed antics, began revealing in public adoration and later enticed Saitama to make a big deal out of it just to entice his own rise in popularity, only to be cut down by a hail of exploding shuriken which sends the crowding masses into a panic. Recognizing Sonic to be the culprit the assailant soon forces his hand by causing havoc around the populated area with a lethal bombardment. Saitama, while still busy looking for hero work to do, realizes Sonic had provided him with the pick me'up he needed and swiftly knocks the latter out cold saving the day. Later that day around Saitama's old neighborhood, a mysterious being was seen skulking around frightening the few masses who lived in the desolate Z-City. Perturbed at not being sent out, Tatsumaki berated the assignment staff, having already sent out A-Class's Golden Ball and Spring Mustache to the area.

In Z-City the two aforementioned heroes are busy patrolling the streets wondering about a rumor they'd heard of about a pretty dangerous monster who lives in said area, after finding next to nothing on the job they eventually find signs of said Mysterious Being and chase off after it. Having run into Kombu Infinity, who'd also heard rumors of a powerful group of monsters in the city, engaged the duo easily swatting the best efforts of both aside. Realizing they are outmatched Mustache dials for reinforcements just before he is swiftly defeated. Upset that his opposition was so weak Kombu sets out to create the rumor he and his fellow monsters initially heard about; soon after Saitama returns from a market sale. When Kombu notices him, the former relents on not having been able to secure some kombu soup stalk just before the monster attacks him. When next seen Saitama is just cooking some kombu soup when Genos comes in.

Manga and Anime Differences

 * Saitama getting the idea for Genos' training from King's book is anime original. In the manga, he just came up with it on his own.
 * Saitama's guess of Sonic's name is Joints-o'-Pain Panic in the manga, Jack-o'-lantern Panic in the anime.
 * In the anime, Saitama directly stops the car from hitting the kid with his arm. In the manga, he bends a tree to stop the car.
 * In the anime, Saitama knocks Sonic down from very high up. They were standing on the ground in the manga. Also, the impact makes a crater in the anime while the road was only cracked in the manga.
 * The scene with Tatsumaki and the Hero Association workers is anime original.
 * Spring Mustache only gives 2 theories for the increased monster activity in Z City instead of the 3 he gave in the manga.
 * In the manga, Golden Ball had his guard up while being dragged through the draining. This was not seen in the anime.
 * Armored Chief Clerk and D-Pad were shown outside at a vending machine when they received the Hero Association notice for help in the anime. In the manga, they were at a restaurant with some other heroes.
 * The Blizzard Group scene is anime original.
 * For the scene where the heroes inspect the damaged building, in the anime, Grave-Eight was replaced with Blue Fire.
 * When the monsters are talking about the ghost town rumors, the silhouette of the Monster Association members is not shown in the anime.

Episode Notes

 * Fubuki gives the episode monologue at the end of the credits.