If you liked Paranormal Activity, you might also like...
The Conjuring
The House of the Devil
Drag Me to Hell
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Land of the Dead
28 Days Later...
The Blair Witch Project
A Nightmare on Elm Street (1984)
Poltergeist (1982)
The Evil Dead (1981)
The Fog (1980)
Salem's Lot
Dawn of the Dead (1978)
Carrie (1976)
The Texas Chain Saw Massacre (1974)
The Exorcist
Tales from the Crypt
Night of the Living Dead
The Birds
Please add other Horror films to the list.