Nerve-jangling and devilishly bleak, “Longlegs” is easily the front-runner for scariest movie of 2024. Set during the drab 1990s of Clinton-era America, the latest offering from writer-director Osgood “Oz” Perkins throbs with a bone-chilling sense of dread, a marvelous piece of supernatural horror wearing the skin of a serial killer thriller that weaves a lasting, sinister spell..