A red herring


Often used in the context of television detective shows, a red herring refers to something designed to distract or throw someone off a trail. Origins of this expression are related to the herring fish that is often smoked – a process that turns it red and gives it a strong smell. Because of their pungent aroma, smoked herrings were used to teach hunting hounds how to follow a trail, and they would be drawn across the path of a trail as a distraction that they must overcome.