Mokkerkalfe or Mökkurkalfe (モックルカールヴィ Mokkurukāruvui?) is a prefabricated giant made out of clay from Norse mytholgy, to assist Hrungnir in his battle against Thor. It was an artificial life form that was made from a mare’s heart contained within a giant mountain-like body of clay. The legend said the mare was so cowardly that Mökkurkalfe could not fight properly and Thor’s servant destroyed it. In the world of Toaru Majutsu no Index the legend is used as a basis for at least two spells.