The Mari Lwyd (the Grey Mare) is a pagan tradition said to bring good luck. People decorate a horse’s skull with decorative ears and eyes attached; adorn it with colorful reins, bells, ribbons and wrapped it with a white sheet and carry it on the end of a pole. Then the group goes door-to-door singing and challenging the families inside to a battle of rhyming insults in Welsh. At the end of the battle of wits (known as pwnco) the group would be invited into the house for refreshments.
Costumed musical performers called "Mummers" or "Soulers" who would go house to house begging for food donations called "soul cakes" in exchange for prayers on All Souls Day are where the tradition of Trick-or-Treating began. - THE ARMAGH MUMMERS. Ireland