Groa
;)
according to Germanic mythology, was a seeress and the wife of Aurvandil, whose froze toe Thor turned into a star by throwing it up into the sky. Exactly who this Aurvandil, or Aurvandill, was remains uncertain, though it has been suggested that he may have been a fertility god of the wetlands. Groa herself tried by magic to remove whetstone fragments from Thor's head after his fight with the frost giant Hrungnir's sharp-edged, three-cornered stone when it had collided with Thor's hammer in mid-air. So excited was Groa, however, by Thor's news about the star and the return of her lost husband that she unfortunately failed to finish the spell, and this was why a few fragments of whetstone remained in Thor's head. Some time after her death, Groa was roused from the grave by her son, Svipdrag, who needed her advice on how he could win the love of the beautiful Menglad.