Sacred Grove Guardians
"We are guardians of this land... Guide us to where we once stood. Only then can you enter the true Sacred Grove..."
The Sacred Grove Guardians make their sole appearance in Twilight Princess. Their primary purpose is to guard the entrance to the ruins to the Temple of Time, and where the Master Sword resides. The Guardians themselves seem to made out of a tough metallic material and they are capable of both speech and movement.
Twilight Princess
Within the events of Twilight Princess, Link has to gain access to the Master Sword to break the curse of his current Wolf form, in which the Master Sword can unlock according to Princess Zelda. After navigating the Sacred Grove itself, Wolf Link will come across a puzzling structure. After howling Zelda's Lullaby, the Guardians will awake.
Link will then have to solve the puzzle. In this puzzle, Wolf Link will have to move strategically around the many platforms. Depending on which movement Link will make, one Guardian will move in the same direction and the other will move in the opposite direction. If facing towards the edge the Guardians will be unable to move and if jumping towards one another the Guardians will clash and return to their original position. Link will be unable to jump towards the Guardian and if one of the Guardians lands on Link, the puzzle will be restarted. Another note is that Link can start the puzzle over again by simply talking to the Guardians. When he has returned the Guardians to their original spot, the land will return to its normal form and the Guardians will return to being dormant. This will allow Link access to where the Master Sword lays.