Dancing Idol
The Dancing Idol (おどるにんぎょう, Odoru ningyō?, lit. Dancing Doll) is a Quest item in Golden Sun: The Lost Age. It is found at the peak of the exterior of Gaia Rock, invisible on top of a white pedestal (cast Reveal to see and take it). It is used in the interior portion of Gaia Rock by placing it on copies of the same style of altar to open paths and create beams of sunlight that will lower the difficulty of the Serpent boss fight in the end of the dungeon.
After completing Gaia Rock and engaging in a lengthy cutscene in Izumo, give this to Lady Uzume and she will give you Coal, a Mars Djinni.
It makes a minor return in Dark Dawn. Uzume passes away some time between The Lost Age and Dark Dawn. The Dancing Idol marks her grave and her spirit can communicate to Himi through it while it does a comical dance. In addition, a larger statue of the Dancing Idol dominates the Yamata Ruins, and it could be inferred to be understood that three eyes of the Dancing Idol reflect on the three Colored Orbs.