Sandworm

Sandworms are giant worm-like guardians on Isle of Gust, their apparent purpose to guard the island's windmills. They normally hide under desert sands before approaching; the only warning of their approach is a distinctive sound and a moving mound of dirt. Until Link treads across their grounds, there are no clues as to if and where they are waiting. After antagonized, Sandworms will appear almost harmless until reaching their destination: Link's feet. Once there, these monsters will leap out of the sands below, eating and chomping on Link. The player can escape faster by rubbing the stylus against the onscreen Sandworm, who will eventually spit out the hero before retreating underground once more.

Since Sandworms cannot see while underground, they apparently rely on sound to find meals. If Link treads quietly while on their grounds, these monsters will not be aware of his presence. Once he starts running or jumping however, Link's cover is blown and the worms will be able to pinpoint his location. He can escape by running onto solid ground where the sand-dwelling monsters cannot reach, or he can distract them with a dropped bomb. Since Sandworms seem to respond to any sound, they will also attempt to eat these explosives. Of course, doing so means their death; bombs are the only way Link can permanently defeat Sandworms. Oddly, Sandworms will always choose going after a placed bomb instead of Link.

Trivia

 * In Japanese, Sandworm is called Moldworm, like the minish-sized enemy in The Minish Cap.
 * Other enemies found under desert sands include Lanmolas, Leevers, and a boss monster known as Molgera. Unlike Sandworms, these enemies will attack whether or not they are provoked.