"Perhaps he hath simply eaten the dirt? 'Tis a simple explanation for how he could have removed such a vast quantity. His hunger must truly be insatiable then if he hath not only devoured mine dirt but also that of several other houses. Perhaps it could even be a curse of sorts? And he is quite methodical in such too, leaving naught a disturbance but the absence of the substance beneath thine pillow! " Don's admittedly not too sure how this Dirt Man managed to get rid of all the dirt underneath her pillow, but perhaps they're like a Distortion in some way. A person who became the Dirt Man and perhaps they simply have a compulsion to devour such a substance.