11 Most Terrifying Sci-Fi Movie Monsters

The giant, nightmarish sandworms in Dune were a triumph of practical effects. Achieved using miniatures for the most part, the colossal-looking toothy slug-likes were exactly as they had appeared in the imagination of every reader.

Sure, the upcoming remake will probably improve their look with the advancement in effects technology, but the originals were still absolutely the stuff of nightmares.

There's just something in their simplicity: they are almost singularly designed for killing, no frills, no superfluous details. Their biology is almost entirely determined by their "job" as a killing machine. And you really have to marvel at the purity of that. You know, while helplessly running away from it.

And it's not like they can be avoided - most terrifyingly, the worms are tolerated not just because their spice by-product is so key to the Dune universe but also because they're basically indestructible.