An Irish grandmother has gone viral thanks to a mischievous prank that helped bring back memories of her childhood. Eighty-one-year old Olive Smyth knocked on a door and ran away, just like she did as a child, while her son Mark filmed the whole thing. The ‘knick knack’, as it’s called in Ireland, seemed to go off without a hitch, despite Mark’s teasing.Mark Smyth gave further details about the prank in an article on the Irish Independent website. Credit: YouTube/Mark Smyth