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 in water, and the shapes foretold the number of future children. Children would also chase crows and divine some of these things from the number of birds or the direction they flew. As noted earlier, 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. Many 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