Dreadfall

It is similar to Halloween, as it arrives also near the end of the year, with a difference of a few months, akin to October, the month of Halloween. The Dreadfall update was also released in Dragons: Rise of Berk, around the time of Halloween. It also brought with it a new type of dragon, the Sunchaser, a subspecies of the Small Shadow. In the Dreadfall update, the skies of Berk are dark, as though it is midnight. This is probably meant to represent the act of trick-or-treat, done throughout the night.