How Adult Swim Made Insane Horror Movie ‘Yule Log’ Without Warner Bros. Discovery Finding Out

"Too Many Cooks" director Casper Kelly reveals how he got away with his risky and innovative genre-bending undertaking on company dime.

Editor’s note: This article includes mild spoilers for “Adult Swim Yule Log.”

All due respect to James Cameron and his underwater actors in “Avatar: The Way of Water,” but you can’t beat the filmmaking gamble of Casper Kelly’s “Adult Swim Yule Log.” Adult Swim’s first feature-length live action endeavor dropped without warning December 11 after the season finale of “Ricky and Morty”: A cozy two-minute yule log video morphs into a disturbing home invasion horror movie that becomes a supernatural cabin-in-the-woods thriller with a young couple (Justin Miles and Andrea Laing) who may be at the mercy of a haunted fireplace.

And then things get really weird, with everything from time travel to UFOs figuring into an unclassifiable odyssey. “My dream has been making movies,” Kelly told IndieWire over Zoom this week. “I thought now that I’ve got one, I’m going to put in everything I can.”

The director behind Adult Swim’s 2014 viral sitcom satire “Too Many Cooks” and the network’s actual 2013 sitcom “Your Pretty Face Is Going to Hell” has a penchant for blending macabre satire with dreamlike concepts straight out of the David Lynch playbook. “Yule Log” takes ambitious swings, including a bleak flashback involving slavery and sudden flashes of gore that wouldn’t look out of place in “Evil Dead.”

Mind you, the studio that produced “Yule Log” is owned by Warner Bros. Discovery, which keeps making headlines for belt-tightening and whittling down HBO Max. How the hell did Kelly get away with it?

“Great question,” Kelly said with a grin. “I’ve worked with Adult Swim for a very long time. We’re friends. For a lot of these things, I can just pitch the premise.”

That division, like Kelly, was based in Atlanta. He said he knew the Adult Swim team well enough to work the system. Since the production of “Yule Log,” that system may have changed after WBD merged Adult Swim parent Cartoon Network Studios with Warner Bros. Animation this fall. However, Adult Swim had a slush fund that allows its executives to greenlight much of its content without corporate approval.

“Part of the trick is doing it cheaply enough enough that they don’t have to go hat in hand and ask for a lot of money,” Kelly said. Though he and Adult Swim declined to offer specifics, sources tell IndieWire that the ceiling is generally in the high six-figure range. (The 4 a.m. shorts, which ran around 11 minutes, were greenlit with budgets in the $75,000 range; “Yule Log” clocks in at 91 minutes.)

Kelly shot the movie earlier this year in a crazed 15 days to ensure that the project could make its seasonal deadline. He’s a confidante of fellow genre innovators like Rodney Ascher (“Room 237”) and Todd Rohal (“The Catechism Cataclysm”), who both consulted on the project, and was a co-writer of breakout midnight hit “Mandy” (and created its famed Cheddar Goblin), but nothing could mitigate the challenge of a ticking clock.

Casper Kelly on the set of “Adult Swim Yule Log”

As conditions at Adult Swim evolved, Kelly felt the heat beyond the fireplace. Walter Newman, the executive who greenlit the project late last year, left the company this fall. As post-production delayed in the face of shifting company priorities, Kelly had to work with six editors — all while keeping “Yule Log” a secret. “I just had to remember that this ecosystem has always been changing,” he said. “You just try to take advantage of where it’s at right now.”

Kelly initially envisioned the movie starting with two hours of uninterrupted log-crackling before the home invasion plot creeps in, but changed tactics when the project secured a high-profile spot after the “Rick and Morty” finale. “We did a 10-minute version and that felt like three years,” Kelly said. “It turns out that two minutes does the job.”

He shot the fireplace-invasion sequence in two days as a single take with diegetic sound, which meant the timing had to coordinate with the actors as they interrupt the static frame. “I was very scared because I didn’t have the time to really test it,” Kelly said. “The way I constructed it, I didn’t have flexibility. I couldn’t shorten it after the fact. If it didn’t work, I didn’t have a lot of options. I couldn’t cut to a closeup and remove a bunch of scenes.”

That was relatively straightforward compared to the many special effects that followed, including a fiery yule log that flies across the cabin of its own volition. Kelly achieved that with a blend of practical effects and work by Brazilian firm NoxusFX, which specializes in fire simulations. In one shot, a character falls down the stairs while grappling with the log; the actor was holding a light. “We were like, ‘There’s no way we can add fire to that, he’s moving around,’” Kelly said. “But that shot ended up looking great.”

An even more difficult challenge was bringing a racial component into “Yule Log.” The white boyfriend of Laing’s character acknowledges her blackness in a cringe-worthy moment, and later the story reveals a history of slavery and oppression on the same property where the events take place.

Kelly is a white Southerner with generations of family history in Georgia and knew the risk. “I’m sure there’s a whole other version of this where it’s just about a funny log going around and killing people and that’s the whole movie,” he said. “I just like to explore questions. This aspect just came out of that and it surprised me.”

His aunt, he said, uncovered family records that revealed that one of his ancestors did in fact own a slave. “So yes, it’s very real to me,” he said. “And it is scary, because it’s such a potent topic. But I decided to take the risk, because I do feel like I have a point of view about it. I think a lot about if I was alive in those times, would I be anti-slavery and progressive, or just following society just like all those other people?”

“Adult Swim Yule Log”

Again: Not your average Adult Swim material. “It was exciting that they were willing to do something that was a little outside of what they normally do,” Kelly said. “It’s not as comedic as would probably be expected for them. I’m just excited I broke the seal and finally crossed over into the filmmaker thing.”

He’s already plotting out a spec script for his next feature and plans to finish writing it next year. “I treated this first movie as a practice run,” he said, and laughed. “I’ll probably do that every time.”

“Adult Swim Yule Log” is now available to stream on HBO Max.