Tremors came out in the golden age of practical effects. Filmed during the tail end of the ‘80s, practical effects craftsmanship was at its peak before CGI began to dominate creature movies. The Tremors franchise has survived, but practical effects haven’t been so lucky. CGI graboids are simply a reality of keeping the franchise alive, but you can spot a few practical ones in Tremors: A Cold Day in Hell, the sixth film.

“There are pieces here and there that we can work with, usually appendages and things like that,” Michael Gross said in a phone interview with Bloody Disgusting. “When you see them en masse, that is to say entire graboids, that is for the most part CGI right now. It boils down to money. It boils down to budget. They can do that more cheaply than they can hiring people to build multiple graboids. So we have graboid parts that are practical and some very large pieces, you will see in Tremors 6, gaping jaws, the one at the end, that is all practical. Where it can’t be avoided. But when they’re in motion and in action bursting out of the ground, many of them are CGI.

For the climax of Tremors: A Cold Day in Hell, Burt (Gross)’s son Travis (Jamie Kennedy) has to crawl through the mouth of a graboid trapped in a crate.

“In this movie, I go into the belly of the beast,” Kennedy said in a phone interview. “So definitely we had a huge practical graboid.

“It was actually pretty comfortable. They made it big. It actually wasn’t that bad. Some people were freaked out that it’d be claustrophobic but I got used to it. It wasn’t that bad at all. I really went down the heart of it. It’s soft and warm and gooey. That’s all I can tell you. Soft, warm and gooey.”

The aftermath of graboid explosions is still practical. Lots of actors get covered in graboid guts in Tremors: A Cold Day in Hell, including Kennedy when he emerges from his Jonah-like journey into a graboid.

“I was covered in goo for the whole morning,” Kennedy said. “We shot that all in the morning so I was in goo for probably about seven hours.”

Even if there are CGI graboids, the surrounding set will utilize practical effects. The graboid may be CGI, but the dirt and floorboards it turns up are real.

“We still have effects where things are pulled underground to simulate graboids underground,” Gross said. “The ground heaving up under a graboid, much of that is practical effects. Things occasionally pulled under the ground or small explosions, all that sort of thing. Things detonated in sequence underground to puff up dirt and things like that. It really is a mix and it depends on the scene. There are certainly times when we do use some pieces but never again as much as we did in Tremors 1.”

Kennedy says A Cold Day in Hell actually has more practical effects than the previous film, Tremors 5: Bloodlines, so that’s good news.

“Tremors 5 probably had more CGI but there were a couple little tentacle shots,” Kennedy said. “For the most part it was more CGI. Obviously, the first one was all practical. But you know, the world’s changing. There is also CGI so I would say it’s a 50/50 mix.”

Tremors: A Cold Day in Hell is on DVD, Blu-ray and digital May 1.