"The Devil and his Grandmother" or "The Dragon and His Grandmother" (German: Der Teufel und seine Großmutter) is a German fairy tale collected by the Brothers Grimm, number 125.

According to Jack Zipes, the source of the story was Dorothea Viehmann, the wife of a tailor from Hesse.

A dragon happens to fly by, however, and offers the three men salvation under the condition that they must serve him for seven years.

The soldiers give the correct answers: a dead sea-cat in the North Sea, a whale rib, and an old horse's hoof.

No longer in the Devil's power, the soldiers live happily ever after thanks to the money-making whip.