Ember Belly

You swallow the oil consumed in the casting of the spell.
Once before the spell ends, you can exhale the oil as a
bonus action, igniting it as you expel it from your body.
Each creature in a 5-foot-wide, 30-foot-long line must make
a Dexterity saving throw, taking 2d10 fire damage on a
failed save, or half as much damage on a successful one.
Once you exhale the oil, the spell ends.