Boulder

More of an obstacle than an enemy, Boulders (originally known as Rocks) are simply rocks that fall in random patterns when Link is traveling through certain mountainous regions of Hyrule, commonly appearing on Death Mountain. They can often be hard to predict and will inflict damage on Link if he comes in contact with them.

Death Mountain
Boulders first appeared as Rocks in The Legend of Zelda. These boulders fall off of Death Mountain near the Lost Hills. They are hard to avoid and often seem to even home in on Link's location. In later games they are more erratic and unpredictable, but no less dangerous. In A Link to the Past they appear on the lower western region of Death Mountain in the Light World and are much larger and able to cause a whole heart of damage. It is easier to travel further up the mountain by travelling through the caves to avoid them. They also appeared on the same mountain in Ocarina of Time, but instead of bouncing down the mountain, they would roll down it once Link has become an adult. In Four Swords Adventures they would also appear on Death Mountain similar to their A Link to the Past appearance, but also show up in caves where they can be pushed, wherein they will roll around like their Ocarina of Time incarnations. This time they can be dropped into pits to make them safe to cross.

Other Locations
Boulders also appeared similar to their original appearance in Link's Awakening and Oracle of Ages, either on the east of Tal Tal Mountain Range in the former, and the Restoration Wall in the latter. In Ocarina of Time Boulders appear in Gerudo Valley and certain dungeons, and sometimes roll around in an unnatural manner around areas such as the passageway prior to the Kokiri Sword and in certain dungeons such as Ganon's Castle, as if controlled by some magic force. In Majora's Mask they behave like they did in Ocarina of Time, but this time appear when climbing the Stone Tower, although a gray variant can be found in the Deku Shrine. In The Minish Cap, Boulders appear notably on Mount Crenel and behave similar to their A Link to the Past incarnation. Rolling boulders also appear on the Isle of Ruins in Phantom Hourglass and the Fire Sanctuary in Spirit Tracks but static varieties are found in other locations and can be pushed to solve puzzles like in Four Swords Adventures, or destroyed by Wrecker Phantoms.

As Weapons
Boulders appear in the battle with the Stone Hinox in Link's Awakening DX when it slams the ground, while regular Hinox in Four Swords Adventures throw massive boulders at the four Links.