Aliens don’t always invade the Earth to colonize it or steal its resources; sometimes they’re just looking out for the welfare of the universe, the Earth, or humanity itself.

In the new remake of The Day the Earth Stood Still, an alien must determine whether he should destroy humanity to save the Earth. Which aliens have come to rescue us? Check out our list.

Klaatu and All Other Space Faring Species (The Day the Earth Stood Still)
Reason for Conquest: In the original film, to prevent humanity from nuking other species and wreaking general havoc on the universe.
Method of Conquest: They don’t actually conquer the Earth, but they make it clear that robot enforcers like Gort are more than capable of dealing with humanity.
Outcome: Warning. Klaatu tells the humans to mend their war-like ways or face certain destruction.

The Alien Planners (Plan 9 From Outer Space)
Reason for Conquest: To prevent humans from discovering a doomsday weapon that will cause sunlight to explode and destroy the universe.
Method of Conquest: Raising the dead to distract humans and sow the seeds of chaos.
Outcome: Failure. After faltering in Plan 9 and Plan 9B, one of the aliens finally fesses up that they just want to keep humanity from destroying the universe, the human hero of the piece punches him in the face. And their spaceship explodes.

The Overlords (Childhood’s End by Arthur C. Clarke)
Reason for Conquest: The Overlords seek to usher humanity into a golden age, and then into its next stage of evolution.
Method of Conquest: Under the general (but not complete) agreement of humanity, the Overlords exert dominion over Earth, granting humans peace and prosperity but forbidding them from pursuing certain creative and scientific activities, such as space travel.
Outcome: Success. Despite some early dissent, humanity comes to accept the Overlords, who help a new generation of humans reach a new level of existence. Things are less happy for the parents of these new humans, who largely commit suicide, and for members of an anti-Overlord sect, which nukes itself.

The Puppet Masters (The Puppet Masters by Robert Heinlein)
Reason for Conquest: According to them, they want to bring humanity the peace and joy of nirvana.
Method of Conquest: Infiltration and assimilation. The sluggy aliens attach themselves to humans, taking over their bodies.
Outcome: Backfire. A resistance movement of free humans discovers a disease that kills the slugs. And once they have finished infecting the population on Earth, a small group takes the battle to the alien’s home, Titan, planning to wipe out the entire species.

The Souls (The Host by Stephenie Meyer)
Reason for Conquest: The souls see humanity as a violent and self-destructive race and believe that their conquest and oppression of humanity is somehow mankind’s salvation.
Method of Conquest: Infiltration and assimilation. The Puppet Master-inspired souls are inserted in human bodies and usually establish complete control of the human’s body and mind.
Outcome: Awaiting a sequel. Some souls join the human resistance movement, but humanity is still working on expelling the souls from Earth.

The Oankali (Lilith’s Brood (formerly Xenogenesis) by Octavia Butler)
Reason for Conquest: Not entirely benevolent, the Oankali need to merge with humans to survive. But they also seek the repair and betterment of the human race, which has been all but destroyed by nuclear war and which the Oankali believe is too violent to continue in its current form.
Method of Conquest: The Oankali capture the remaining humans and give them the choice of either submitting to the Oankali and interbreeding with them or being made sterile.
Outcome: Compromise. Some humans agree to interbreed with the Oankali, but one of the half-Oankali children convinces the Oankali to allow humans to remain human and live and breed on Mars.

The Galactic Council (The Amazing 3)
Reason for Conquest: The council decides that humanity is a threat to the universe and too dangerous to live.
Method of Conquest: Rather than messy invasion, the council opts to destroy it with a small super bomb.
Outcome: Delay. After initially ordering the destruction of Earth, the council is eventually swayed to give Earth more time to develop and sends their agents back to continue their evaluation.

The Monitors (The Monitors)
Reason for Conquest: To police humanity and save it from its own terrible impulses.
Method of Conquest: Aside from setting up a government and police force led by polite fellows in bowler hats, they attempt to win over the public by flooding the airwaves with testimonials and obnoxious jingles.
Outcome: Failure. Humanity might like cleaner streets and less crime, but won’t abide the Monitors’ ban on politics, sex, and violence. But when humans oust the Monitors, they’re still oppressed, just by other corrupt humans rather than benevolent but controlling aliens.