D&Dtools

You can modify your breath weapon to manifest on the Ethereal Plane instead of on the Material Plane.
(You must be on the Material Plane, or on another plane with a coexistent Ethereal Plane, for this spell to function).
Your breath weapon affects ethereal creatures as if they were material, and does not affect material creatures in its area.
The modification applies only to the breath produced as part of the casting.