Source: Planar Adventures, pg(s). 242
A moon hag appears as a withered woman whose face stretches tightly over her skull, with a fat, red, bulging eye.
Moon hags almost always serve Groetus, and many claim to be his mouthpiece. They often use their knowledge about the secret paths and portals of the Boneyard to journey to the Material Plane, usually to sire and abandon changeling daughters, whom they also see as agents of Groetus.
Moon hag changelings are especially pale-skinned, and many are plagued by chronic anxiety and tend to be reclusive.