L • Turn Ethereal (Su). Once per day, a Moonswyft may enter the Ethereal Plane at will, for 10 minutes. Doing so will tire the Moonswyft and he will be fatigued for the end of the day. If the Moonswyft is already fatigued, he will instead become exhausted, and take 10 points of nonlethal damage.
Read carefully. Would you rather I specify it as a Free Action?