11.The portkey
Let’s start with something rather innocent and inconsequential. Portkeys are magical items designed to transport people and return them to their starting point. Harry and Cedric Diggory are transported by one of these in Goblet of Fire during the Triwizard tournament. Cedric is killed by Peter Pettigrew and Harry has a duel with Voldemort. He manages to use the portkey to return to Hogwarts, but instead of the center of the maze where they found it, it transports him all the way to the entrance. It isn’t affecting the story much, but still a plot hole nonetheless.