In Greek folklore, the mischievous goblin appearing during the twelve days of Christmas is the kallikantzaros.
Kallikantzaroi are malevolent seasonal goblins said to emerge from underground during the Christmas period. In the usual Greek reckoning, their active season runs from 25 December through 6 January, ending with Theophany, or Epiphany. They enter homes through chimneys, spoil food, break furniture, frighten people, and play disruptive pranks.
A famous story says that kallikantzaroi spend the rest of the year sawing at the enormous tree supporting the Earth. When Christmas arrives, they abandon their work to torment humans. On Epiphany they return below ground, only to discover that the tree has healed and their labor must begin again.
Descriptions vary by region: they may be hairy, horned, tailed, goat-footed, donkey-eared, lame, or even tiny. Traditional protections include keeping the fireplace burning, marking doors with a cross, burning unpleasant-smelling objects, or leaving food as a bribe. Krampus is a separate Alpine Christmas figure, while satyrs belong to ancient Greek religious and literary traditions rather than this specific twelve-day cycle.