Crystal Dragon's Breath

You touch one willing creature and imbue it with the power to spew magical energy from its mouth, provided it has one. Choose Force, Psychic, fire, Necrotic, or Radiant. Until the spell ends, the creature can use an action to exhale energy of the chosen type in a 30-foot beam that is 5 feet wide. Each creature in that area must make a Constitution saving throw, taking 3d8 damage, and dealing an additional 1d8 force to all creatures within 5 feet of them, of the chosen type on a failed save, or half as much damage on a successful one.