Disk of Destruction

This spell creates a circular, horizontal plane of radiant energy that is 3 feet in diameter and is 1" thick, which floats above the user's hand. This disk can be launched at one target that are within 75' of the point of being launched. When launched, the disk produces a sound similar to a sawblade. 

If launched at the intended target, the target will need to make a Dexterity Saving Throw. On a failed save, this attack does 6d8 radiant damage (8d8 radiant damage for undead targets) and half damage on a successful save. Once it hits its intended target it explodes on impact, causing enemies within a 20' range to make a Dexterity Saving Throw as well. On a failed save, each target will take 2d8 radiant damage (3d8 radiant damage for undead targets), and half damage on a successful save.