Ethereal Sleep

Roll a d20 before you begin a long rest.  On a roll of 5 or higher, as you fall asleep your body begins to separate from your consciousness. Your body is transported to a harmless demiplane in the ethereal.  While you sleep, a visual of your body remains on the host plane.  This visual cannot interact with its surroundings but can be damaged.  If the visual is damaged, the caster must make a concentration check to maintain asleep.