Moldworm

Moldworms, also known as Moldorms, Swamolas, and Sandworms, are subterranean enemies that first appear in The Legend of Zelda. They appear as giant worms or centipedes, depending on the game, and typically have many segments.

The Legend of Zelda
In The Legend of Zelda, Moldorms are worms with many identical segments. They come out of the center of sandy rooms and start winding around. To defeat them, Link must hit the last segment, causing them to shrink one segment at a time.

The Legend of Zelda: A Link to the Past
In The Legend of Zelda: A Link to the Past, Swamolas are green and leap out of the water of the Swamp of Evil in the Dark World. They act similar to the Lanmola boss in the Desert Palace and are said to be related, but are much shorter.

The Legend of Zelda: Majora's Mask
In The Legend of Zelda: Majora's Mask, two giant Moldorms comprise the fourth boss, Twinmold. In The Legend of Zelda: Majora's Mask, young Moldorms called Moldbabies are added to the fight.

The Legend of Zelda: The Wind Waker
In The Legend of Zelda: The Wind Waker, a giant Moldorm called Molgera appears as a boss, while smaller creatures (possibly normal Moldorms) assist it in battle.

The Legend of Zelda: The Minish Cap
In The Legend of Zelda: The Minish Cap, Moldworms hide under the ground in areas only accessible while small, primarily near Lon Lon Ranch, and slowly emerge segment by segment before slowly looping around, quite similar to their first appearance. However, they also try to eat Link. If they succeed, he will travel through each segment before coming out the back, at which point he will take damage and become dirty, which attracts nearby Pestos to him. While underground, a small moving bump of dirt can be seen where their head is.

The Legend of Zelda: Twilight Princess
In The Legend of Zelda: Twilight Princess, Moldorms now pursue Link from under the sand in Gerudo Desert and early in the Arbiter's Grounds, leaping at him when they get close enough. They have three large fangs in this game.

The Legend of Zelda: Phantom Hourglass
In The Legend of Zelda: Phantom Hourglass, Sandworms appear much larger and live on the Isle of Gust and the Temple of Wind. Here, they hide under the sand and will burst out to eat Link if they hear him making too much noise, likely in reference to giant sandworms in franchises such as Dune and Tremors. They will also go after bombs, which will kill them, and will in fact stop pursuing Link in order to eat a bomb.

The Legend of Zelda: Skyward Sword
In The Legend of Zelda: Skyward Sword, Moldworms appear in Mogma Mitts-accessible tunnels and appear as centipedes. They have weak tail ends, similar to those of boss Moldorms, inspired by the enlarged abdomen of the honey ant. Destroying the tail end causes the Moldworm to shorten and pick up speed, but it will be defeated after three hits.

The Legend of Zelda: A Link Between Worlds
Based off their A Link to the Past design and behavior, Swamolas in The Legend of Zelda: A Link Between Worlds appear in Misery Mire, itself essentially a renamed Swamp of Evil. Fiery versions called Flamolas appear in Turtle Rock.

Link: The Faces of Evil
Moldorms appear in Ganon's Lair, where they resemble their original artwork as large earthworms. They simply crawl back and forth, though their short size makes them difficult to hit with the sword.