I recall being entirely squicked out by the giant sandworms in the film version of "Dune." Now, if I so choose, I can recapture and own that feeling by following Instructables user canida's directions for making a sandworm costume.
The clever costume design begins with a $13 kid's-play tunnel. After that, you need 6 yards of sandworm-tan fabric, mouth-pink fabric, posterboard, wire, and a large cardboard box. You will need some basic sewing skills to pull the costume off, but the end result is a wonderfully squirmy and toothy worm outfit.
Granted, the costume is pretty far from life-size. The fictional worms can get up to 1,300 feet long and swallow mining equipment (not to mention people) whole, but you'll just have to make do.
Canida talks about how the costume makes for a great geek test. Do people recognize you as a sandworm, or do they think you're from "Tremors," or a Sarlacc from "Star Wars?" Does it remind them of the "Dune" books, the movie, or the miniseries? You might have to carry a full spice rack with you as a clue.