Welcome to another edition of Trope Tuesday, where we hit up the black hole of productivity and investigate a literary theme or device that helps our favorite entertainment chug along. This week, we’re hitting on one that many Expanded Universe fans are intimately familiar with: Retroactive Continuities, or Retcons.

Reframing past events to serve a current plot need. When the inserted events work with what was previously stated, it’s a Revision; when they outright replace it, it’s a Rewrite. The ideal retcon clarifies a question alluded to without adding excessive new questions. In its most basic form, this is any plot point that was not intended from the beginning. The most preferred use is where it contradicts nothing, even though it was changed later on.

While the term comes from comic books, dating to All-Star Squadron #18 in 1983 and shortened to “retcon” by the end of the decade, the technique is much older. Often, it’s used to serve a new plot by changing its context; however, it’s also done when the creators are caught writing a story that violates continuity and isn’t very plausible.

In Marvel Comics, the person who pointed out the problem and at the same time provided a plausible explanation was awarded a Genuine Marvel Comics No-Prize by editor Stan Lee, a tradition that was kept alive by other editors after he became publisher.

See also Ass Pull, which is something that was not properly set up before it is sprung on the audience. It is related to Deus ex Machina. Some but not all retcons are Ass Pulls, and a good retcon can actually improve the current narrative. A good way to get away with a retcon is to reveal new implications or motivations for events that have already been established.

Where do you even start in Star Wars? This is a franchise that ties itself into knots trying to explain away any minor-to-major inconsistency that crops up whenever a new book accidentally invalidates something an older book said. Or when The Clone Wars television series simply steamrolls swaths of the Expanded Universe. The latter (among other things) got author Karen Traviss to ragequit right before she was scheduled to start writing the Fate of the Jedi series.

You know retcons are important to a franchise when they hire a guy to keep tabs on all of them. Hello, Leland Chee, the Keeper of the Holocron.

Granted, all sorts of series in all sorts of mediums have needed to resort to retcons to keep things straight. The Other Star Franchise, anyone? No one, however, seems to be in the same league as Star Wars when it comes to making sure anything and everything fits into a lone canon.