Growing up in a rowhome during a 95-degree humid suburban Philadelphia summer, neighbors swung their doors open just to catch a piece of breeze. Kids scootered, scampered, and when it got too hot – went inside a darkened living room to chomp freeze-pops and see what movie marathon was toiling through the summer afternoon. 

In the mid-90s, TNT was the champion of Tremors. Fourth of July comes around and the lightning bugs are out? You know there’s gonna be a TNT Tremors marathon. Steaming myself on the porch one summer day, I first got a taste of this so-called “Tremors” franchise by overhearing my brother inside the neighbor’s living room: 

“Oh my God, this Tremors has the Ass Blasters worms. Those are Ass Blasters!” 

I watched Dune for the first time this summer. It had been on my long list and it was time to venture out into the Arrakis desert land. As the first sighting of this bristle-toothed land monster erupted from showers of soil, all I could think was: 

“Are these Dune worms ass blasters?” 

It turns out that, no, the Dune worms are not ass blasters. They are the Shai-Hulud, or for our intent and purposes – they are big-ass visual effects. 

An audience unfamiliar with the Dune universe might say, “Dune totally ripped off their sandworm idea from Tremors.” But Frank Herbert wrote the original Dune in 1965, so maybe Tremors is the real ripper-offer here. Doesn’t matter. 

Because it’s the comparison we deserve, but not the one we need right now. Shush, Commissioner Gordon. Doesn’t matter if we need it. Let’s talk about movie worms.

The Graboid-Shai-Hulud aesthetic cage fight.

sandworm size chart

Photo courtesy of

First off, if you’ve never siphoned off an entire afternoon of your life to watch a Tremors marathon, the Tremors worms are called Graboids. Stand a fully mature Graboid up against an adult Dune sandworm, and these are the measurements at the pay-per-view weigh-in: 

Graboid worm: 10 meters long, 2 meters wide, 10-20 tons
Primary weapons: Hooked mandibles, three gyrating tongues that snatch prey like a Venus flytrap. Dominick DeLuca of Bloody Disgusting called Graboids “the shark of the desert.”
Top speed: 20 MPH in loose soil
Weakness: Repeated shotgun blasts from Reba McEntire
Sensitivities: Rhythmic sound

Shai-hulud sandworm: Up to 400 meters long, 100 meters wide, weight undetermined
Primary weapons: Gaping bristled mouth capable of swallowing ships
Top speed: Up to 50 MPH
Weaknesses: By hooking open the worm’s ring segment plates, the worm can be forced to stay above ground without submerging. And water is lethal!
Sensitivities: Rhythmic sound

In a fight, this would be like pitting an anaconda against an earthworm. Unless of course, the earthworm sprays the anaconda with a water gun.

Worm appearance.

Graboids and Shai-hulud are cousins. They’re like trout and salmon. They are both creatures of the desert. Thick, rigid pebbled skin. Beige, gray, and sandstone-colored bodies. Mouths that open like bottomless abysses of death.

And the prehistoric aura that surrounds both of them? Totally intentional.

The practical effects of a Graboid: Animating a worm in 1990

The two visual effects studios to work on Tremors were Fantasy II Film and 4WARD Productions. Fantasy II Film grew its pedigree in the 80s into the early 90s when they worked on Aliens, The Abyss, and the first two Terminator films. The Abyss won “Best Visual Effects” at the ‘90 Oscars and Fantasy II Film’s name was further enhanced by a Terminator 2: Judgment Day “Best Visual Effects” win for Gene Warren Jr., Dennis Muren, Stan Winston, and Robert Skotak at the 1992 Oscars. While Muren and Winston didn’t work on Tremors, this crew would win a combined 13 Oscars in their lifetimes (so far). 

Tremors also employed a massive creature special effects team spearheaded by Creature Effects Designer and Creators Alec Gillis and Tom Woodruff Jr. The pair had recently founded Amalgamated Dynamics studio for their creature effects work and had the opportunity with Tremors to challenge their artistry on a large scale. The effects crew and artists worked together with first-time director Ron Underwood to achieve a realistic portrayal of worms barreling through a desert set built in two months by Production Designer Ivo Cristante. Underwood talked in a 2019 interview about the difficulty of translating the concept to real-world execution: 

We tried to make everything sort of simple and foolproof as possible. However, most of the effects didn’t work the first time. As with most effects movies, it just became agony – for me as a first-time director, too – whatever you planned for, something else happens. And the effects were certainly often that way, especially the physical effects.     

Honestly, Underwood was being modest in his assessment of “simple and foolproof.” The visual effects team applied a diverse range of ingenious practical tactics to build shots that live on gleefully in film history. He got specific about a scene where a poor trailer park couple are harassed by a hungry Graboid and swallowed up in the night, which involved trying to sink a car in a water pit filled with gravelly vermiculite.

Then they had to replicate the terror of a Graboid burrowing towards its victims, and Underwood described this process:    

Another one [effect] that actually worked, though, was the moving hump that went throughout the desert and was racing toward Kevin Bacon at the end of the film at the cliff. And that was a…technically, a trough dug by a tractor out in the desert and we put a boat buoy in the trough, covered the whole trough with a dirt mat, and then pulled it with a truck. And it really gave the sense of the moving hump of this creature. 

Before any of this could happen, effects masters Woodruff and Gillis had to design the worms. quoted Gillis as he described the influences for the Graboid: 

What we did not want to do was repeat what had been done in Dune. Because in Dune, the Sandworms were like earthworms, sort of more muscular, you know. They seemed to be kind of like a long muscular tube — rather than anything with a skeletal structure or armor plating.

Score, there it is! Direct Dune reference. Gillis and Woodruff went on to describe thinking of the Graboid’s propulsion as similar to a killer whale, with the skin combining the textures of elephant skin and crocodile skin. Gillis later described crafting the head with the influence of a snapping turtle, and you can see this in his working sketches:

Physically, the Graboids were an amalgam of crafty movie material: aluminum bands for the head sections, foam latex skin for an illusion of naturally wrinkling skin, and resistant fiberglass for the mandibles, head, and neck. 

So many scenes in Tremors are summarized by a Graboid bursting and squealing from the soil to terrorize fleeing humans. To articulate the Graboid, the effects crew dug a 12-foot pit and hooked cable controllers to the segmented pieces. It took six crew wearing respirators in the dust-filled pit to move the pieces, and the actual soil-bursting effect was achieved by building a ten-foot elevator. The elevator operated pneumatically and lowered the puppeteer underground for each take. The elevator “burst” upward at a rate of about 12 miles per hour.   

Alec Gillis talked in a 2020 Tremors Youtube channel interview about his influences for becoming a monster maker. When you hear his answer, you can see that an entire franchise of people-eating worms has roots in the fascinated mind of a little kid:  

Sometimes he would wake me up [his father] at nine or ten o’clock at night when I was like five years old and say, “You gotta come see this!” I’d come out and be rubbing my eyes and it would be [the] Ray Harryhausen movie, Jason and the Argonauts, with the skeletons coming out of the ground and sword fighting, and I think something about being a little kid – impressionable little kid – and having just awakened these images, were kind of burned into my brain, and started me off on a life of fascination with creatures and effects.

Thirty-one years later: The VFX of Dune

The birth of Tremors compared to that of Dune is a tale of two movies with glaring developmental differences. Tremors was a modestly budgeted original screenplay written by Steven S. Wilson and Brent Maddock, with a first-time director, that made a little over $16 million domestic against its $10 million budget. Dune was an adapted screenplay by Jon Spaihts, Denis Villeneuve, and Eric Roth that had a $102 million budget, an experienced director, and a cast made almost entirely of leading actors. 

Where both films were similar was their dedication to making some sexy-ass worms.

Unfortunately, the VFX artists on Dune were not willing to go the distance and craft a 400-meter practical worm. Come on, now. 1200 feet of articulated worm is too much? What VFX Supervisor Paul Lambert and the artists of DNEG did instead was craft a worm that – like Tremors – drew influence from reptilian and marine life. 

Remember that Alec Gillis and Tim Woodruff Jr. utilized a pebbled texture akin to a crocodile or elephant in making the Tremors worms. While you’d be hard-pressed to find any elephant in the sandworm, it’s easy to make a reptilian comparison to Tremors when you see how DNEG approached the sandworm’s body texture. Lambert said in a 2022 IGN Youtube video

“What we came up with is this idea that the worm is actually made of these hard plates and in between these plates, you had this soft membrane.”

The rigid armor-like plates of a Sandworm in Dune (2021)

The rigid armor-like plates of a Sandworm in Dune (2021)

“Hard plates” paired with “soft membrane” sounds like a turtle. Or a Stegasaurus. Whatever the association, it’s got a prehistoric aura, and Director Denis Villeneuve said as much in an Empire interview quoted by Indiewire

“It was a year of work to design and to find the perfect shape that looked prehistoric enough.”

The parallels continue. The same way that the Graboid propulsion was designed with a killer whale in mind, Peter Lambert and his team had to figure out how to properly animate the movements of a massive, fluid, and revered creature: 

We investigated earthworms – how they move. We investigated snakes – how they move. Basically, any creature who moved in that particular vein, we experimented with. What became apparent was things became very biological and very clinical. Things didn’t look cinematic at all.  

What they found through trial and error was that rippling sand looks like rippling water. They were thinking in the wrong biosphere. To get their worm right, they had to take their animation perspectives into the deep sea. Lambert spoke in the IGN interview about when they felt they had found their creative approach: 

You see footage of a whale, like cresting waves and smashing through waves, and the more and more iterations we did, it actually started to feel like it was more of a “sand whale.” 

Nothing is more apparent in the final design of the Shai-hulud than when it opens its mouth and the audience is greeted with thousands and thousands of bristles – just like a baleen whale.

The great baleen mouth of the Dune sandworm

The great baleen mouth of the Dune sandworm

Looking back at Tremors versus the CG-heavy nature of Dune, it provokes a practical effects purist to yearn for another era. Lambert described in a interview that the film wasn’t entirely CG effects – they provided meticulous set extension work to replicate a year’s worth of concept art by Denis Villeneuve and Production Designer Patrice Vermette. 

In the same interview, Lambert discussed the practical model they used to shoot the sandworm scenes: 

We wanted something alive but prehistoric. One reference we had for that was elephant skin. Rigid plates over spots and areas with soft membranes in between, folding like an accordion. Obviously, not super agile on this scale – the turning circle of a being like that would not be small. 

We have now officially come full circle back to Tremors with the fabled elephant skin reference. All that’s missing from the Dune production is six men in respirators toiling under ten feet of sand to articulate a sandworm.

1990’s Tremors and 2021’s Dune are eternal soulmates.

No matter how much the Tremors crew said they didn’t want to replicate a Dune worm – or vice versa – the two movies are eternally bonded. 

Two generations of artists took the concept of a blind invertebrate, scaled it up, and infused it with 60 million years of sea mammal musculature and plates of lost Dinosauria. They built creatures tethered to the desert that could make an audience feel immersed in lush fauna. Living on in both of these movies for the rest of cinematic history is a simple shared lesson: 

When you feel the sand start to move beneath your feet, run for your life.  

Dune: Part Two will release theatrically on November 3, 2023. Tremors is currently available for rent on Apple TV, or take it way back and dust off that old VHS player.