 Technically, a human invasion of an alien species is also an alien invasion, as from the viewpoint of the aliens, humans are the aliens.Such stories are much rarer than stories about aliens attacking humans.Examples include the short story "Sentry" (1954) (in which the "aliens" described are, at the end, explained to be humans), the video game "Phantasy Star II" (1989), "The Martian Chronicles" by Ray Bradbury, the Imperium of Man in the Warhammer 40,000 universe, "Invaders from Earth" by Robert Silverberg, Ender's Game, the movies "Battle for Terra" (2007), "Planet 51" (2009), "Avatar" (2009) and "Mars Needs Moms" (2011).