UPDATE: We spoke to more of the writers and directors of these films here. Original story below.

Viewers watching various Fox networks over the past week have been visited by some strange and chilling advertising just in time for Halloween. For this, they can thank Fox and Mars candy brands, which teamed up to get up-and-coming horror directors to make disturbing short films—which have been running in their entirety during commercial breaks.

Four “Bite Size Horror” films (they are all two minutes long) have rolled out so far. The one that’s gotten the most attention is “Floor 9.5,” presented by Skittles, written by Simon Allen and directed by Toby Meakins. (Allen and Meakins previously worked together on the Vimeo staff pick horror shorts Breathe and LOT254.) “Floor 9.5” ran during a Yankees-Indians playoff game on FS1 last week, and judging by the Twitter reactions, it clearly freaked people out.

The film tells the creepy tale of an office worker who gets stuck between the 9th and 10th floors of a building while riding the elevator. When the elevator doors open, she sees a man standing in the shadows, facing away from her. He asks for her help, and against her better judgment, she obliges…

Skittles “Floor 9.5”

Director: Toby Meakins

Writer: Simon Allen

Stars: Robin Berry, Georgina Campbell, James Cunningham

The three other films that have rolled out so far are presented by M&Ms, Starburst and Snickers.

The M&Ms film, “The Road,” features a dad and his daughters visiting a desolate stretch of road that’s rumored to be haunted by the ghost of a motorcycle rider who died there.

M&Ms “The Road”

Directors: Jack Bishop, Justin Nijm

Starburst “Replacement”

Starburst’s “Replacement” concerns a young boy who is visited by, and then usurped by, a frightening, masked doppelgänger.

Director: Christopher Leone

Stars: Jack McGraw, Aidan McGraw

Snickers “Live Bait”

Finally, Snickers presents “Live Bait,” a tale of a fisherman on whom the table are suddenly turned.

Director: Andrew Laurich

Writers: Gabriel Miller, Andrew Laurich

Star: Brian Donahue

The films are very well made. Obviously, it’s easier to present something convincing when you don’t have to squeeze the brand or product into the plot. (The giant product images that lead into the films were apparently the compromise here.) But underwriting long-form content like this, in a deal with a broadcaster to air on its network and cable properties, makes for a very entertaining product—and reflects well on the brands themselves.

AdFreak spoke with “Floor 9.5” director Toby Meakins and writer Simon Allen about their creepy creation. Meakins said the idea for the plot came from a pile of unused ideas that Allen has lying around his office.

“The fragment was a single line—someone being followed from the front,” says Meakins. “We thought how weird and creepy that would be, if someone was always a few steps ahead of you no matter which way you turned. We plugged that into the loop/hell of ‘Floor 9.5,’ which is intended to be a metaphor for modern working life.”

Meakins said he wanted “Floor 9.5” to feel like a “short Kafkaesque nightmare.”

“It had to be all about tone and atmosphere rather than creating jump scares,” he said. “Don’t get me wrong, I love a good jump scare, but if you can chill someone to the bone, the film tends to stay with the audience. We also wanted it to feel contemporary, like a two-minute Black Mirror, to find create a situation that anyone could imagine themselves in and then twist it.”

Allen added that many supernatural ideas work better in short form than in an hour-long TV episode or feature film, “where their impact is often diluted by the demands and distractions of a longer narrative. It’s a lot easier to hold the audience’s attention and to exert more control over their specific experience, which, in this case, was intended to be a standard haunted-elevator story that suddenly becomes something much more unsettling about the physics of movement and ‘following.'”

The campaign was created by Fox Networks Group’s integrated agency All City. Tony Sella from All City is the executive producer of the campaign, and Arby Pedrossian from Fox Digital Studio is the producer.

We’re told that as many as 12 short films may have been shot for this “Bite Size Horror” series. We’ll try to track down the others this week.