This one was created by aliens, which had invaded Earth in ancient times.

The race, now numbering close to half a million, were poised to invade Earth with a fleet of 200 ships.

His missions generally involved killing aliens that have invaded Earth.

If that happens the aliens will be able to disguise themselves as humans and invade Earth.

She then teaches him about how demons invade Earth to hunt and find women to breed with.

In the possible future known as 2099, the Phalanx invaded Earth.

Wells had written, long ago, of aliens who had invaded Earth.

The Scrin, meanwhile, plan to invade Earth with a larger force.

Aliens have invaded Earth, and have built four land bases.

After a series of events and acquaintances, the two boys discover that aliens were beginning to invade Earth.