subversive life form from outer space theme

Aliens, creatures, or some other form of life from outer space, come along and (usually gradually) subvert the civilization on a target planet until the point where it is merely an extension of the invading life form's way of life.

Examples

In tng1x25 "Conspiracy", bug-like aliens from outer space subvert the higher echelons of Starfleet by secretly attaching themselves to the brain stems of its key leaders.

25 total · 9 choice · 16 major

StoryLevelMotivation
ahp5x10 choice The grand revelation of the story was evidently that some mushroom-like aliens had seeded Earth with human-co-opting space spores as a prelude to invasion.
movie: Body Snatchers (1993) choice Spacefaring pod plants hatched a nefarious plot to replace everyone in the world with utterly emotionless replicas.
movie: Invasion of the Body Snatchers (1956) choice Alien plant spores have fallen from space grown into large seed pods, each one capable of reproducing a duplicate replacement copy of each human.
movie: Invasion of the Body Snatchers (1978) choice Alien plant spores fallen from space grew into large seed pods, each one capable of reproducing a duplicate replacement copy of each human.
movie: Seedpeople (1992) choice Spacefaring seeds had hitched a ride to the Comet Valley community on a meteor and began to takeover the townspeople. The taken over people acted utterly emotionless thereafter.
movie: The Invasion (2007) choice An alien virus was turning people into emotionless beings after arriving on Earth on a crashed space shuttle constitutes a main novelty of the film.
pkded1x07 choice Body snatching aliens were replacing people with physically identical, but oddly behaving duplicates.
rbt1985e3x12 choice The grand revelation of the story was that some mushroom-like aliens had seeded Earth with human-co-opting space spores as a prelude to invasion.
tng1x25 choice Federation compromised by bug aliens
futurama6x08 major Space cats enslaved humanity by means of their cuteness.