You create a sphere that encapsulates a creature you can see in range that is glowing with a brilliant light. The creature must make a Dexterity saving throw or be captured in the sphere, the spell fails on a success. The sphere releases radiant energy from its radioactive shell causing the creature to take 4d8 radiant damage upon entry and during the end of each of its turns. The shell of the sphere has 30 hit points and is resistant to non magical bludgeoning, piercing, and slashing damage. If the shell is destroyed the spell ends, as well as if the casters concentration is broken.