A type of vampire within Greek folklore. All children born in the week between Christmas and New Years were considered unlucky, and believed to be destined to become vampires after their death. These vampires, the callicantzaros, were distinct in that their attacks were limited only to Christmas Day and the 12 days following. During this time period, the callicantzaros would seize people and tear them apart, and when the time was up, they would fall back into a remote netherworld until the next year.