Paranormal Activity has many alternate endings, and they're all just as scream-worthy as the one audiences know. One of those endings has Katie killing her boyfriend Micah downstairs, then returning upstairs to slit her throat in front of the camera. Yeesh! Gruesome much? You can thank Steven Spielberg’s suggestion of inserting the theatrical ending we know and terrifyingly love, in which we see a demon-faced Katie fly at the camera.