Mysterious Beings who have survived a punch from Saitama

This set of armour, used to seal in my immeasurable, irresistible power has been broken.



Having become too powerful as a result of his training regiment, Saitama is now capable of defeating almost all of his opponents, particularly Mysterious Beings, with only a single punch. The power behind his punches is so great that many monsters, including Dragon-level threats, seem to "explode" when struck. However, there have been a few rare occasions that some of them have been able to survive one of his punches, not knowing the exact amount of power he has put into his fist. Nevertheless, none have been able to give Saitama a real challenge as he's been having to greatly hold back his true strength, leaving him bored and unsatisfied.

Against human opponents, Saitama holds back even more and only uses enough strength to incapacitate or knock them out.

Boros
Boros was the first on-screen opponent of Saitama that survived after getting punched, much to his surprise. In his fight with Saitama, Boros was hit with 3 normal punches, a Consecutive Normal Punches attack, as well as the shockwave from the hero's Serious Punch. After this, Boros was fatally injured on the ground but still conscious for a short period of time before his death. Saitama even considered him to be the strongest opponent he had faced so far.

Overgrown Rover
Overgrown Rover encountered Saitama when the latter was wandering in the Monster Association Headquarters, and upon seeing him, Rover viciously bombarded the hero with its energy blasts, until he was annoyed by its misbehavior and punched it out of consciousness. The punch was powerful enough to shake the entire Monster Association Headquarters. Despite having taken significant damage from the punch, Rover managed to survive, though for this case, it's due to Saitama treating it as a huge dog, whom he tried to tame, even trying to offer him a bone.

Orochi
Orochi met Saitama when the hero was wandering in the Monster Association Headquarters in order to figure out whoever was responsible for the noises below his apartment. During their fight deep underground, Orochi was defeated by a single punch from Saitama that blew his body apart, although the Monster King has managed to survive and absorb blood from other creatures in order to regenerate from the damage. Though if Saitama punched Orochi's heart, he likely wouldn't have survived.

Garou
After defeating Sage Centipede, Garou encountered Saitama. At first, it appeared Garou had been defeated in one punch, but he was able to recover and fight the bald hero soon later. During the fight, Garou has taken multiple attacks consisting of punches and slaps from Saitama and still managed to keep going. More surprisingly, after transforming into his Cosmic Fear Mode under the influence of "God", Garou was even capable of taking many Serious Punches from Saitama before ultimately being defeated.

In the original webcomic, after defeating Golden Sperm and multiple S-Class heroes, Garou, in his awakened state, challenged Saitama. He is the second character to continue fighting after multiple punches from Saitama and was able to dodge some of his punches, having received at least 7 normal punches, a Consecutive Normal Punches attack, as well as an exchange with Saitama's Two-Handed Consecutive Normal Punches, and a Serious Headbutt. After all of this, Garou still had enough energy to escape.

Evil Natural Water
In the manga, after Evil Natural Water merged with the ocean and grew exponentially in size, becoming Evil Ocean Water, Saitama hit it with a Serious Punch dispersing it entirely, with its eyes still remaining intact. It managed to survive but was reduced drastically in size with not much water remaining to it.

In the original webcomic, when Evil Natural Water interrupted Saitama before his fight with Awakened Garou, he splattered it with a single punch, causing the water to rain down onto the ground. Despite its apparent death, the monster was revealed to have survived later. Although it was reduced drastically in size, with not much water remaining to it (similar to the manga).

Trivia

 * Although Kombu Infinity is still alive after its fight with Saitama, it is unclear whether he has defeated the monster by punching it, as the battle was off-screen.
 * It is unknown if Men's Esthetician Man survived being punched by Saitama, as he was a Mysterious Being but looked very much like a human.