Samhain step from guising to playing pranks". Playing pranks at Samhain is recorded in the Scottish Highlands as far back as 1736 and was also common in Ireland, which led to Samhain being nicknamed "Mischief Night" in some parts. Wearing costumes at Halloween spread to England in the 20th century, as did the custom of playing pranks, though there had been mumming at other festivals. At the time of mass transatlantic Irish and Scottish immigration, which popularised Halloween in North America, Halloween in Ireland and Scotland had a strong tradition of guising and pranks. Trick-or-treating may have come from the custom
Samhain and when livestock were slaughtered for the winter. As at Bealtaine, special bonfires were lit. These were deemed to have protective and cleansing powers and there were rituals involving them. Like Bealtaine, Samhain was seen as a liminal time, when the boundary between this world and the Otherworld could more easily be crossed. This meant the "Aos Sí", the 'spirits' or 'fairies', could more easily come into our world. Most scholars see the "Aos Sí" as remnants of the pagan gods and nature spirits. At Samhain, it was believed that the "Aos Sí" needed to be propitiated to ensure that