Paul held himself apart from the humor, his attention focused on the projection and the question that filled his mind: "Thufir, are there sandworms big enough to swallow that whole?"
Silence settled on the table. The Duke cursed under his breath, then thought: No—they have to face the realities here.
"There’re worms in the deep desert could take this entire factory in one gulp," Thufir said.
Here's a weird, great geological feature I spotted yesterday while out hiking in rural Oklahoma. We were out in a flat, flat plan that was dotted with a few tall, angular sandstone mounds and narrow sandstone canyons carved out by erosion. This rock was sticking out of the side of one of the mounds. It was the only place we saw anything like these vertical, tube-like structures, which stretched from the ground up to probably about my shoulder.
When I posted this image on Twitter yesterday, several people suggested that the tubes might be skolithos — tube-shaped fossils that were probably made by some kind of ancient worm creature and turn up sometimes in sandstones. While the pictures on Wikipedia don't look very similar to what I saw, there are apparently lots of different forms these things (and similar tube fossils) can take.