Mari Lwyd (possibly translating to "Holy Mary"), is a folk custom found in South Wales, which occurs around Christmas and New Year.
A group of people would hide under white blankets, and hold sticks with a horse's skull attached. This group would go from house to house and sing a song in which they requested entrance. The inhabitants would offer excuses why they could not let them in, and the party would sing a second verse. When the inhabitants ran out of excuses, the party would be let in, and be provided with drink and food.