Meteor

The meteor was a giant extraterrestrial rock that threatened the destruction of Z-City and its surrounding areas. It was assigned a disaster level of Dragon.

Appearance
The meteor was a giant oblong rock that glowed upon entering the planet's atmosphere.

Giant Meteor Arc
Astronomers detect an asteroid heading toward earth. It suddenly shifts its trajectory and aims for Z-City. All S-Class heroes are called to deal with it but only Bang, Bofoi, and Genos respond. The meteor withstands Bofoi's missiles and Genos's full-powered blast with no apparent damage. Saitama arrives and shatters the meteor with one punch. However, the meteorite fragments scatter across the city. Although there are no fatal casualties, Z-City is left devasted.

Physical Abilities
Immense Kinetic Energy: The meteor was assigned a Dragon-level threat, which means it has the power to destroy multiple cities. Even after Saitama destroyed the main body, its fragments had enough power to ruin Z-City. It was marked a 6 to 9 on the Torino scale.

Immense Durability: The meteor was able to withstand the firepower of Metal Knight's missiles. It also took Genos's fully powered incineration blast with no apparent damage.

Trivia

 * The reason why no other S-Class heroes were there during the giant meteor arc was because of the short time (35 min)..
 * This is the first categorized disaster level that is not an organic being.