Rosemary's Baby

Rosemary's Baby is the unseen "villain" from the movie of the same name - although never seen (in fact for most of the film the baby is unborn) the baby's arrival is met with fear and anguish by it's mother due to the fact she believes that it was conceived by the Devil himself: Rosemary finds herself doubting her own sanity as she becomes convinced of a Satanic conspiracy against herself and as the movie progresses her fears start to become more and more irrational.

Ultimately Rosemary's fears are shown to be based on horrible reality and she awakens to find herself surrounded by Satanic cultists (who were disguised as friends and family) - they then lead her to see her baby, which has been born and lays in a crib - the film ends with Rosemary seemingly accepting her fate as the mother of the demonic baby, which remains unseen to the audience.

Although Rosemary's Baby did not show any malice or villainy in itself the events leading up to its birth were definitely evil and the fact that it was spawned by the Devil himself the audience is left to make its own decision on the ultimate outcome of the story: though given the extreme anguish Rosemary went through we are left with a less-than-hopeful outlook on the future as the unseen child has seemingly already gained considerable power in preparation for a Satanic uprising.