About the AUEdit
In this AU, members of the Big Four are cast as cave-people of prehistoric times. As the name implies, the setting usually mirrors The Croods, though this is not required.
Like Guy Hiccup likes to come up with new ideas and ways, build, name and show them to those that can also use them, like a family of homeless cavemen. Toothless is portrayed as Belt, as the two journey to Tomorrow with the family.
Merida and her family (with the witch as her grandmother) are cast as the Croods, with Merida as Eep. Angus and the witch's crow are one of the many animals that later joins the family.