The Kallikantzaroi are malevolent goblin-like beings from Greek folklore said to live underground, spending most of the year sawing at the World Tree that supports the Earth. During the Twelve Days of Christmas (from Christmas Day to Epiphany), they surface to cause mischief, damage homes, spoil food, and terrorise villages before being driven back below when the waters are blessed. Protective traditions, such as keeping fires lit, burning old shoes, or using basil and holy water are still remembered in rural areas, and the creatures remain a central part of modern Greek Christmas folklore and cultural storytelling.