Helen Sloan/HBO Warning: Spoilers ahead for HBO's "Game of Thrones" season eight finale. HBO's showrunners David Benioff and D.B. Weiss once said they were told three shocking moments George R.R. Martin that haven't happened in the books yet. The first two were the burning of Shireen Baratheon and the revelation of how Hodor got his name. The third and final shocking moment likely just unfolded on the series finale. Visit INSIDER's homepage for more stories. HBO's "Game of Thrones" came to an end on Sunday night, and with it one of the show's most devastating deaths in the eight-season run.