Here’s what that mysterious fog in the finale really means.

It: Welcome to Derry team debunks The Mist fan theory: ‘There is no connection’

Here's what that mysterious fog in the finale really means.

By Nick Romano

Nick Romano is a senior editor at ** with 15 years of journalism experience covering entertainment. His work previously appeared in *Vanity Fair*, Vulture, IGN, and more.

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December 14, 2025 11:00 p.m. ET

Pennywise's fog spreads throughout town in 'It: Welcome to Derry'. Credit:

**Warning: This article contains spoilers from *It: Welcome to Derry* season finale, "Winter Fire."**

*It: Welcome to Derry* expands on the lore of Stephen King's *It* universe, with series creators Andy and Barbara Muschietti making note of *The Dark Tower* and *The Shining*. However, the sibling filmmaking duo are here to debunk one other popular fan theory still lingering out there.

Ever since fans caught the show's official trailer launch in September, revealing a mysterious fog that rolls through the entire town of Derry, viewers have speculated about a possible connection to *The Mist*, another classic King horror story.

"There is no connection to *The Mist*," Andy Muschietti, who directs multiple episodes, including this Sunday's season 1 finale, tells ** definitively. "I'm sorry to disappoint everyone with this."

So what is this fog exactly? In the finale episode, titled "Winter Fire," we see it weave through the suburban Maine streets, which the entity uses to its advantage to child nap the entire high school student body. It's also present when both the kids and adults race to the frozen lake to stop Pennywise from escaping its cage.

Chris Chalk's Dick Hallorann stuck in the fog of Pennywise on 'It: Welcome to Derry' finale.

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"It has its own logic," Andy explains. "You see it in episode 4 at the end when Taniel [Joshua Odjick] is telling the story and we see how the asteroid hits the Earth. After the explosion, we see the Deadlights are basically surrounded by this smokey fog that trails back. We decided to make that the language of It's expansion."

The filmmaker wanted to find a visual way to depict It as an expansive force. "If it wasn't for the indigenous community in the 1600s, It would have expanded across the world, but It's caged," he continues. "Now that the pillars are lifted and the cage is open, I wanted to convey visually that force of super nature is expanding out."

*The Mist* is a 1980 novella about a mysterious, dense mist that pours into the town of Bridgton, Maine, bringing with it vicious monstrosities from another dimension that attack anyone lost in its cover. The tale was notably adapted into the 2007 movie starring Thomas Jane and the 2017 Spike TV series starring Morgan Spector.

Brad Caleb Kane, a longtime King aficionado who showruns *It: Welcome to Derry* with co-creator Jason Fuchs, points out the key mythology reason why this couldn't be a *Mist* connection.

Thomas Jane in 2007's 'The Mist'.

Weinstein Company/Courtesy Everett Collection

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"Not to get too nerdy, but for that to be *The Mist*, there would've had to have been a portal opened up into Todash Darkness, specifically," he says, using the specific name for the monster-filled void in between universes that brought the creatures to Earth in that King story.

He also explains the book connection that led to the inclusion of this Pennywise fog. In the climax of King's source material, the Loser's Club have their final battle against the entity, which coincides with a flash flood.

"It really is a direct consequence of that fight that's going on and the psychic and spiritual power that the being has and its fear and its anger," Kane says. "That creates these very specific conditions in Derry. You can parallel that here because there is a great, emotional thing happening for the creature, realizing that the lane is open for it to get out into the wider world."

All episodes of *It: Welcome to Derry* are now available to stream on HBO Max.

Original Article on Source

Source: “EW Horror”