Warning: If you're not caught up with "The Walking Dead," both the show and the comic series, there are some spoilers ahead. "The Walking Dead" season five finale is Sunday evening at 9 p.m. Right now, Rick and his group are living (relatively) safely behind the walls of Alexandria. (Though after last week's episode, Rick may be messing up the group's chance at living zombie free.) If you're a fan of the series, and especially the comics, you're probably wondering when the next big villain is coming to town.