A fan or super fan who can't wait to ruin an ending or plot points to show how much of a fan they are then others, these people think by telling you everything about a show, movie, book and so on that they are the #1 fan in the world and a leading expert on all things media and cutting edge
"This King Nerd thought it was a good idea to shout out the ending of the movie in the lobby then went on Facebook and made a post ruining the plot and surprise at the ending."