As an action, make a weapon attack.

On a hit, add 2d8 + your spellcasting ability radiant damage to the attack’s damage roll and mystical dim light glitters on it, causing the next attack made against it to have advantage if it is made before the end of your next turn.

On a critical hit, add twice as much damage.

On a miss by 4 or less, add half as much damage.

Augment

You can increase the damage by 3d8 for each additional mana expended.