Huldrefolk

The Huldrefolk are first mentioned in Dragons: Titan Uprising, specifically in the description of "New Years Stormfly.

Dancing
The Huldrefolk were the first practitioners of a traditional dance style that is practiced by the Vikings of Berk during the celebration of Hogmany.

Trivia

 * The Huldrefolk are named after the Norse mythological Huldr (also spelled huldra), which were a race of female forest spirits that possessed the tail of a cow and would attempt to seduce men before leading them to their deaths.