The third film in Paramount Pictures' low-budget fright franchise, which was No. 1 at the box office, had the biggest debut ever for a horror movie, according to Sunday studio estimates. It broke the previous record part two set a year ago with $40.7 million. It's also the biggest opening ever for an October release, topping the $50.35 million Paramount's "Jackass 3D" made last year."Paranormal Activity 3" is actually a prequel, with the discovery of disturbing home-movie footage from 1988. Henry Joost and Ariel Schulman, who made the creepy documentary "Catfish," took over directing duties this time.