Guru-Guru

Guru-Guru is a recurring character in the Legend of Zelda series. He is a man who is seen constantly playing something that resembles a combination of a grinder organ and a phonograph. While he's mild-mannered and cheerful most of the time, certain actions can make his face turn into a freakish mockery of his usual expression and his organ grinding speeds up, effectively distorting the song it plays. He is also obsessed with things that go "around and around".

Guru-Guru is often associated with the "Song of Storms," the song that his strange instrument plays. He's seen and heard playing the song in all of his three appearances.

The Legend of Zelda: Ocarina of Time
Guru-Guru can be found in the Windmill in Kakariko Village playing the "Song of Storms" on his grinder organ. When Link is a child, Guru-Guru is trying to come up with a musical theme inspired by the Windmill. When Link comes to the Windmill as an adult, Guru-Guru is visibly upset. According to him, seven years before, a child with an ocarina played a song that "messed up the windmill". When Link takes out his ocarina, Guru-Guru is reminded of the kid with the ocarina, but despite this he teaches Link the "Song of Storms". When Link has learned the song successfully, the mill-wheel starts spinning rapidly, effectively upsetting Guru-Guru even more. If Link then plays the "Song of Storms" for Guru-Guru as a child, the Windmill will spin out of control and drain the well.

At the end of Ocarina of Time, Guru-Guru can be seen during the celebration at Lon Lon Ranch, with Kokiri holding the top of his instrument upside-down, causing him to spin around in the air.

The Legend of Zelda: Majora's Mask
Guru-Guru is a musician employed by the Gorman Troupe, and seems to be the music player for the Rosa Sisters. During the day, he plays his grinder organ in a room in the Stock Pot Inn. During the night, he plays his phonograph near the Laundry Pool, this due to the fact that the other members of the Gorman Troupe kicked him out of their room due to the loud volume of his instrument.

If Link talks to him near the Laundry Pool at night, he will regale him with a tale of his youth. At one point, Guru-Guru was a member of an animal troupe. However, he disliked the fact that the troupe's leader was a dog. Despite this, he shows obvious respect for the dog's leadership abilities. The leader had a mask that could make even the smallest animal follow behind him in a line. However, the envious Guru-Guru stole his mask. After confessing his crime, Guru-Guru is relieved, and gives Link the Bremen Mask.

The Legend of Zelda: Oracle of Seasons
Guru-Guru plays his grinder organ near the Windmill in the Eastern Suburbs. If Link gives him Engine Grease to oil his squeaky Windmill, he will give Link a Phonograph as thanks. This is part of the trading quest for the Noble Sword.

Etymology
The name Guru-Guru seems to be a reference to the Japanese onomatopoeia kuru kuru, referring to something going "around and around".