Uka'toa's Vengeful Eye

You invoke the wrath of Uka'toa a bright yellow eye opens in the ground beneath your target 5ft in diameter. the creature must make a charisma saving throw or be incapacitated in the sickening yellow light and take 3d10 lighting damage. 

If the target moves the eye stays directly underneath of the target until it saves on the saving throw or until the spell ends.