Although the most obvious Halloween costume contest prize was split between Donald Trump and Margot Robbie 's Harley Quinn this year, a solid finalist is expected to be Eleven by Millie Bobby Brown from Stranger Things . This is hardly surprising, mind you. Stranger Things is the most talked about series on Netflix since the first season of Orange is the New Black , and the announcementof a second season, which will arrive sometime in 2017, was expected as if the recipe for a homemade cancer cure was being handed out overnight.