Bahamut's healing Breath

 Until the spell ends, can take a Magic action to either exhale a 15-foot Cone of light that heals all targets apon hitting them 1d6 or exhale a 25-foot Line of radiant power, creature in that area makes a Dexterity saving throw, taking 2d6 damage of the chosen type on a failed save or half as much damage on a successful one.

Using a Higher-Level Spell Slot. The damage and healing increases by 1d6 for each spell slot level above 2.