Break the Hells

You thrust the Hellbreaker into the ground, as it cracks and parts with a sudden localized earthquake. Each creature in a 20-foot cone must make a Dexterity saving throw. A creature takes 4d6 radiant damage on a failed save and falls prone, or half as much damage on a successful one. Until the end of your next turn, the ground becomes diffcult terrain, and creatures that start their turn there take 2d6 radiant damage.