Ethereal

Ethereal creatures exist on a plane (known as the Ethereal Plane) which is parallel to the physical, Material Plane. When a creature is Ethereal, it is invisible and Insubstantial compared to Material objects and creatures. It can float in any direction without regard to any gravitational force, moving at half its normal Skirmish Speed (that of the Material Plane). It can see and hear into the Material Plane, sensing the location of creatures and objects up to 60 ft away.

An Ethereal creature cannot affect creatures or objects on the Material Plane, but can affect those on the Ethereal Plane normally. Force effects present in the Material Plane extend into the Ethereal, but not vise versa.