Following the destruction of the Core of Light, the Crystal Eye was stolen by the Cyclopses, who desired it enough to name a castle after it. Guided by Diggs, the Skylander arrives at Crystal Eye Castle, defeat the Cyclopses, and reclaims the Eye.
Once the Crystal Eye returns to the Ruins, it is connected to the unfinished Core of Light, which causes a large prism to rise from an underground magma pool beneath the machine.
The Crystal Eye in Skylanders: Spyro's Adventure (PlayStation 3 / Xbox 360)
Trivia[]
The Crystal Eye possesses the power to restore the sight of those in its proximity, as demonstrated when Diggs claims that his blurry vision suddenly became "super clear."