The no-budget ghost story “Paranormal Activity” arrives 10 years after “The Blair Witch Project,” and the two horror movies share more than a clever construct and shaky, handheld camerawork.

Like its predecessor, “Paranormal Activity” has been making waves through a viral marketing campaign that has been building positive buzz through early, sold-out college town screenings and Internet chatter. And, like “Blair Witch,” “Paranormal Activity” is bound to divide audiences who have absorbed the hype.

Best advice: See it early in its run — and late at night in a packed theater. Half the fun of the movie comes from the communal experience of sharing in something that feels like it hasn’t been market-tested within an inch of its life.

Micah (Micah Sloat) has bought a video camera to document the weird stuff that has been happening in the two-story San Diego home he shares with his girlfriend of three years, Katie (Katie Featherstone). The young couple consult a psychic (Michael Bayouth), who senses the bad mojo and refers them to a demonologist.

Micah’s solution is to set up his new camera on a tripod at the foot of the couple’s bed and document what happens while they sleep.

The movie’s genius comes from its slow-building tension as it returns night after night to this fixed location, a time code running in the lower right corner of the screen. The bedroom door leading to the upstairs hallway is ajar ... and then it’s not.

The thinness of the premise is laid bare toward the end, but not enough to erase the horror of those silent, nighttime images seen through Micah’s bedroom camera.

“Paranormal Activity” owns a raw, primal potency, proving again that, to the mind, suggestion has as much power as a sledgehammer to the skull.