A movie poster showing a sheet of mono-yellow coloured wallpaper might typically wash over your head.

Not this one. It's instantly recognisable to millions - and inspires dread.

This is Hollywood's latest horror film - Backrooms - and it knows its audience: one more drawn to whispered horror than A-list names, monsters and gore.

Backrooms are essentially disturbing, abandoned rooms with seemingly no end in sight. It could be an empty office block, a hallway or a corridor - unsettling between-zones.

The concept came about in 2019, when anonymous users on message board 4chan were asked to "post disquieting images that just feel 'off'."

One user posted an image of an abandoned office space, with mustard yellow wallpaper and fluorescent lighting.

The post read: "If you're not careful and you noclip out of reality [gaming terminology for glitching or disappearing] in the wrong areas, you'll end up in the Backrooms, where it's nothing but the stink of old moist carpet, the madness of mono-yellow, the endless background noise of fluorescent lights at maximum hum-buzz, and approximately six hundred million square miles of randomly segmented empty rooms to be trapped in."

The post continued: "God save you if you hear something wandering around nearby, because it sure as hell has heard you."

The concept then grew into a hugely popular YouTube mini-series, with creator Kane Parsons, then 16, at the helm. Parsons used a CGI programme called Blender to create environments beyond his budget. Today, the series boasts more than 200m views.

It proved so captivating that Hollywood studio powerhouse A24 - which is behind Oscar-nominated horror The Substance - enlisted Parsons, now 20, for a film adaptation, which was released on Friday [29 May].

Parsons, now A24's youngest ever director, has one solemn tip for survival in the Backrooms: "Make peace with it before anything else, because I don't like to give false optimism."

His task in 2023 was clear: to drag this isolating hellscape kicking and screaming onto the big screen, and in a way that resembles his YouTube series.

He tells me that what excited him most about the project was using a Hollywood budget to dive deeper and bring a "real physicality" to ensure the film feels "distinct from the YouTube series".

He says the team behind the film achieved this by building a vast 30,000 sq ft set based on his Blender designs. It bears similarity to Parsons' first YouTube video - "Found Footage" - which has 80m views and featured shaky 90s camcorder footage of the eerie, yellow office block.

"I think it lets us buy into the characters to a greater degree," Parsons says.

A24's adaptation, written by Will Soodik, uses the concept of the Backrooms to explore mental health.

Oscar nominee Chiwetel Ejiofor stars as Clark, a frustrated furniture store salesman struggling following the breakup of his marriage.

As tensions grow between him and his therapist, Mary, played by Renate Reinsve, Clark discovers the store's route to the Backrooms - a space that begins to prey upon the pair's unresolved traumas.

The big screen lure of the Backrooms reflects the online rise of a very particular fear: the idea of a liminal - or transitional - space.

Neuroscience and architecture expert Meredith Banasiak, who researches the link between buildings and human wellbeing, says hallways and doorways often spark this fear.

This creates what is known as the doorway effect, which confuses our brains. "When spaces start blending together, the way we remember blends too," she explains.

The Backrooms takes this to the extreme - a physical symbol of memories "dissolving into themselves".

As Clark tells Mary in the film: "The more times [the Backrooms] remembers something, the less it does."

Banasiak says her research, and other academic papers, suggests trauma survivors often find these spaces challenging.

The Backrooms has a forum on Reddit, with more than 350k subscribers. Forum moderators say there's something "deeply existential" about the concept and that it's less about monsters and "more from the uncertainty of what else might already exist in the space with you".

TikTok is filled with Backrooms-themed clips - cumulatively topping 30bn views - highlighting the popularity of this 90s-themed landscape with Gen Z.

There's a crossover with gaming, too, with a free Backrooms survival title available on Steam, and similar experiences on offer on Roblox.

Internet researcher Gunseli Yalcinkaya says a mournful nostalgia for pre-internet memories and spaces, and the isolation of the Covid pandemic, may explain why young people are drawn to ideas like Backrooms.

Yalcinkaya says it captures the dissatisfaction of what it means to be a young person today, "where reality is constantly being mediated through screens - there's already a sense that reality is glitching, nothing feels real anymore".

As business publication Fast Company noted, Backrooms is among several recent liminal space titles "shaped by Gen Z's most traumatic formative years".

These include YouTuber Markiplier's horror film Iron Lung, adapted from a video game and set in a submarine. Independently released, it has taken over $50m (£43m) worldwide.

The online trailer for Backrooms quickly became one of A24's most-viewed uploads, with 31m views. The question, of course, is whether this online fever converts to offline ticket sales.

For Matthew Frank, author of The Ankler's Crowd Pleaser newsletter, the YouTube-to-big screen pipeline "feels like a sea change".

Hollywood executives are looking to internet-native culture for audiences and for film-makers like Parsons.

Frank says Backrooms executive producer Chris White discovered Parsons' work after his teenage son insisted he watch it. Another internet-native film-maker, Curry Barker, 26, also released his horror Obsession in cinemas this month, after a similar breakthrough.

It helps the studios too that these names come with "preset audiences" at a time when cinema is struggling against streaming.

Early projections for Backrooms "look really promising", says Frank. It is expected to easily exceed its $10m (£8m) budget and "feels like an event in the way that few movies are able to reach."

"Backrooms has this appeal as a piece of internet‑native IP to the audience," Frank adds.

As for Parsons, headlines in the media have made much of how young he is to be directing a Hollywood film - a focus that tires him.

He was worried his relative inexperience could impact perception, but it "never came up" on set, he tells me.

"Almost immediately it was just us, in a vacuum, talking about the project… I like to think I made up for any lack of experience by being completely obsessive."

Parsons, and perhaps Hollywood, have found plenty to explore in The Backrooms. Can they escape? No way.

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