Meteor

The meteor was a giant extraterrestrial rock that fell to Earth and 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 Earth'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 then arrives and shatters the meteor with one punch. Although its momentum is halted, the meteorite fragments scatter across the city and leave it devastated. There are no fatal casualties.

Physical Abilities
Immense Kinetic Energy: The meteor was assigned threat level of Dragon, which means it had the power to destroy multiple cities. Even after Saitama destroyed the main body, its fragments still 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. Though it's stated by Genos that he can destroy the meteor after his post-Elder Centipede Fight upgrades.

Trivia

 * The reason why no other S-Class heroes were there during the giant meteor arc was because the meteor struck on short notice, and most heroes were too far away to reach it in time. (35 min).
 * This is the first categorized disaster level that is not a living being.
 * The meteor was said to earn a 6 to 9 rating on the Torino scale, a real-life scale used to measure the threat of meteorites.