As an action, you can create a vial of liquid whose liquid is ghostly transparent. A creature can drink the contents as an action to gain the ability to see through solid objects to a range of 9 meters. Within that range, the creature has darkvision if it doesn’t already have it. For the duration, the creature perceives objects as ghostly, transparent images.
This vision can penetrate most barriers, but it is blocked by 30 centimeters of stone, 2.5 centimeters of common metal, a thin sheet of lead, or 90 centimeters of wood or dirt.