Karius og Baktus are the tooth trolls created by Norwegian author Thorbjørn Egner, first appearing in his 1949 children's book and later in the well-known 1954 animated film. The two tiny characters live in the mouth of a boy named Jens and gleefully drill holes in his teeth until he learns to brush properly. In Norway the story remains a cultural touchstone for teaching children about dental care, so short clips of their voices are instantly familiar to many Norwegian listeners. Online, the line has been shared as a reaction sound, especially by fans who grew up with the story.