Sööbik ja Pisik

The main characters are black-haired Karius and red-haired Bactus (red haired) whose names are actually puns on Caries and Bacteria. The point of this is that they are two small "tooth trolls" that live inside cavities in the teeth of a boy named Jens, so the story has a strong tooth health message for children. Karius and Bactus have a very good life, especially when Jens eats white bread with syrup and fails to brush his teeth afterwards. Eventually their homes are destroyed by the work of a dentist and they are rinsed out of Jens' mouth through proper dental care. The story of Karius and Bactus, with its funny pictures and important message, has become a classic of Norwegian children's literature