Like the Title says this portrays a local custom called Hulken I participate in each year on New Year's Eve. Everyone meets up in pairs or groups and dresses up in costumes, some matching like the sheepdog and his herd in this dressup, some not so much. Much like on Halloween in the USA they go from house to house and get sweets or alcohol, depending on age
. Considering that this is a custom originating from an island where almost everyone knows each other, as an added difficulty one has to guess who is under the costume^^