DC Universe canceled its new original series, "Swamp Thing," last week after airing just one episode, despite positive reactions from both critics and fans.

Sources close to the production who spoke to Business Insider described being shocked by the show's cancellation, and said the set was buzzing with anticipation for more episodes.

A source involved in the production said there was chatter on set that WarnerMedia was considering folding DC Universe into its own upcoming streaming platform, which will also include HBO and Cinemax.

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DC Universe's latest original series, "Swamp Thing," was abruptly canceled on Thursday with no explanation, despite positive reactions from critics and fans alike. The series had only aired one episode on the streaming platform, which launched in September, and episode two became available on Friday.

Seven people close to the production, who wished to remain anonymous, told Business Insider they were shocked by the news that "Swamp Thing" was canceled.

The James Wan-produced horror show, based on the DC comic book, has a 92% critic score on Rotten Tomatoes, and "#SaveSwampThing" immediately began trending on Twitter after the series was canceled.

"Cancellation came as a surprise, 100%," a producer on the series said. "It came out of left field."

Read more: DC Universe has canceled its new series 'Swamp Thing' after airing just one episode, despite a 92% rating on Rotten Tomatoes

The first season was originally going to be 13 episodes, but production abruptly shut down in April after the season was cut to 10 episodes. Despite this, the seven people said they had little inclination that the show was in trouble, and even expected more seasons to come, especially after the show started getting good buzz.

"We walked away with the sets standing," the producer said. "We didn't tear them down and go home."

One source close to the production told Business Insider that the show had a possible three-season arc, and the feeling on set was that it could have gone past that if it was a hit, with characters spinning off into their own shows. The source used the specific example of a potential "Justice League Dark" team-up series.

But while the full 10-episode season will stream, and episodes debut every Friday, the series won't return for a second season.

When asked for comment by Business Insider, DC pointed to a community post on the DC Universe website.

"We appreciate there are questions as to 'why,' but unfortunately we are not in a position to answer at this time," the post said.

The internet had its own theory for the cancellation

Without a detailed announcement from DC Universe, speculation began swirling online that the series was axed due to confusion over funding for the film program in North Carolina, where the series was filmed.

But the North Carolina Film Office director, Guy Gaster, told Business Insider on Friday that the state government's budget miscommunication had "no impact whatsoever" on "Swamp Thing."

Warner Bros. was actually approved for $16.9 million — $4.9 million for the "Swamp Thing" pilot, and an additional $12 million for the rest of the season. The Star News reported that the season's budget was around $85 million.

"The parameters of all of these programs are up front," Gaster added. "It's not something that comes as a surprise to the production."

Crystal Reed as Abby Arcane in "Swamp Thing." DC Universe

Crew members were as shocked as anyone

So why was a well-reviewed series with a possible multiple-season story arc and an enthused fan base suddenly canceled after its debut episode?

While the show was expensive, the producer who spoke with Business Insider didn't believe that was the main factor. The producer said the show was budgeted accordingly, and everyone understood the North Carolina film-grant program.

READ MORE: DC Universe is off to a hot start with 3 original TV series that rival Netflix in quality, but it has a big challenge ahead

"We knew we were getting good stuff on set and we kept hearing that the studio was very happy," a crew member said. "There were also a lot of sunk costs where it felt like if things were going well at all, they'd probably keep going because they had so much invested in it. The swamp we built was incredible and was a very expensive set to build."

A separate source involved in the production said the swamp set cost roughly $2 million. Below is a photo of the swamp set one crew member provided Business Insider:

A photo of the swamp set from "Swamp Thing," which a source told Business Insider cost around $2 million. "Swamp Thing" crew member

But another potential reason for the cancellation, beyond the high cost, was a shift in strategy at WarnerMedia, DC's parent company, which formed in the merger of AT&T and Time Warner last year.

A source who worked on the show said there was buzz on set that WarnerMedia might fold DC Universe into its own upcoming streaming service, which is also expected to include HBO and Cinemax. That means WarnerMedia could have an alternate vision for DC Universe than originally expected, which could have influenced the "Swamp Thing" cancellation.

This is the first sign of trouble for DC Universe, which has released four original shows so far (including "Swamp Thing") that have all been received well by critics and fans. It plans to release an animated "Harley Quinn" series and the second season of "Titans" later this year.

If you have a tip about "Swamp Thing" or DC Universe, contact the author at tclark@businessinsider.com.