Features inanimate (but usually in motion) space debris that threaten to collide with important things that need protecting.
Alternate name: Comets
The first video game about Asteroids was released in 1977.
Note that technically comets are treated separate of asteroids, but for our (UVL) purposes the difference is insignificant: comets are asteroids covered in volatile matter such as ice and eventually become asteroids once the matter has worn off enough. The distinction comes mostly from the assumption that comets have different origin than asteroids.