The Probert Encyclopaedia of Norse Mythology

GREIP

In Norse mythology, Greip was a daughter of Geirrod. She with her sister Gjalp tried to kill Thor by changing into a cat and, arching her back under Thor's chair, trying to crush Thor against the ceiling. However, Thor wedged his unbreakable staff between the chair and the ceiling and the two sisters broke their backs in the effort and died.
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