Rat Hole

Rat Holes are small openings in walls that serve as homes to rats in, and , Real Bombchu in , and both in.

The Wind Waker
In, rat holes appear in dungeons such as Dragon Roost Cavern. If Link tosses some All-Purpose Bait in front of a rat hole, a rat will come out and offer to sell him something. Potions and All-Purpose Bait are the wares most frequently sold by these rats. The presence of rats doesn't necessarily mean that a rat hole can be found in the area, as seen within the Submarines floating about the Great Sea.

Four Swords Adventures
In, rat holes appear in the Temple of Ice and Tower of Winds, two levels of Frozen Hyrule. Real Bombchu will keep coming out unless the Links solve a specific puzzle in the room where the rat hole is.

Phantom Hourglass
Only four of these holes appear in, appearing in two pairs. In both cases, a rat holding a small key will emerge from one hole and run to the other. In order to get the key from the first rat (located in the Mountain Passage on Mercay Island), Link must push a block in front of one hole, then, once the rat runs to it, corner it. In order to get the key from the second rat (located in the Temple of Fire on the Isle of Ember), Link needs to kill it with the Boomerang while it is running from one hole to the other.

Similar holes also appear, however, and serve as doorways only accessible by Bombchu and Gongoron.

Spirit Tracks
Rat holes make another appearance in Spirit Tracks. They are occasionally seen in the Tower of Spirits. If a rat comes out of its hole and is seen by Phantom Zelda, she will cower in fear until Link defeats them. Rats will keep coming out unless Link pushes a block in front of their hole, thus preventing any more from emerging.

Trivia

 * In if Link drops All-Purpose Bait in front of a Rat Hole, Rats will stop appearing as enemies in that room until Link leaves, whether he buys something from the Rat or not.