The comma, colon, em dash sentence is yesterday's triple threat

14 Punctuation Marks That You Never Knew Existed

                                                                    A little teaser for ya:

                                          

Also called the Percontation Point and the Irony Mark, this one's used to indicate that there's another layer of meaning in a sentence. Usually a sarcastic or ironic one. So it is essentially a tool for smart people to use to make stupid people feel even stupider. Which makes it the best punctuation mark of all.