Like its predecessors, V/H/S/ Halloween, which premieres Oct. 3 on Shudder, has a framing narrative, although it’s unconnected to, and thus doesn’t explain the origins of, the rest of its on-videotape shorts. In it, Blaine Rothschild (David Hayon), COO of The Octagon Company, oversees trials of the conglomerate’s newest soda, Diet Phantasma, from a secure room behind a two-way mirror. The terrors of Diet Phantasma (“made with real ghosts!”) prove a running gag throughout V/H/S/ Halloween, whose action is otherwise divided into five separate tales of supernatural pandemonium. The finest of those is the first, director Anna Zlokovic’s “Coochie Coochie Coo,” whose title comes from the phrase uttered by its villain, “The Mommy” (Elena Musser), who preys upon teenagers Lacie (Samantha Cochran) and Kaleigh (Natalia Montgomery Fernandez) on Halloween. While its “Diet Phantasma” segments faintly recall Halloween III’s marriage of corporate and paranormal evil, V/H/S/ Halloween plays with the holiday’s familiar conventions and signature imagery without overtly shouting out to, or duplicating, its legions of big-screen horror predecessors.