Blessed Hammer

You summon four spectral hammers that circle around you at 15 feet. Whenever an enemy comes within 15 feet of you, one of the spectral hammers has a chance to hit it and you can make a melee spell attack as if it is an attack of opportunity, dealing 1d6 + your spell casting modifier force damage on a hit and knocking the target prone. If a creature is within 10 feet of you this spell does not affect that creature.