Aldeus's Supernova Smite

The next time you hit a creature with an attack within 10 feet of it during this spell's duration, you cause the creature to glow with a mystical dim light until the spell ends. Any attack roll against the affected creature has advantage if the attacker can see it, and the affected creature can't benefit from being invisible. 
As a reaction, you can end the spell early, causing the creature to erupt in a radiant explosion akin to a supernova. Each creature in a 10-foot-radius sphere centered on the affected creature must make a Dexterity saving throw or take 5d6 thunder damage, 5d6 radiant damage, and be pushed 10 feet away from the affected creature. The affected creature cannot be forcibly moved in this manner.  A creature that succeeds on its saving throw takes half as much damage and is not pushed away from the affected creature.