Cubone
It pines for the mother it will never see again. Seeing a likeness of its mother in the full moon, it cries. The stains on the skull it wears are made by the tears it sheds. (Ruby/Sapphire) It wears the skull of its dead mother on its head; when it becomes lonesome, it cries loudly. (Fire Red)*reads first part* Aweh D: it misses it's mom poor thing I want to hug it now... ;-;
*reads last part* O-oh... Why are you wearing her skull? And using one of her bones as a weapon? What trainer would want you?!!!