Moebius is a mud server, written in python using MySQL as a back-end. It's design goals are to be extensible without taking the engine down, to be distributable via the database, and to allow a complete python coding/learning env online. It

They involve time travel and an alternate timeline. They were originally intended to be the show's series finale (like "Lost City" of the previous season and "Full Circle" before it), but became the eighth season finale after the series was once again renewed.

The two tracks are continuous forming a single circuit or 'Moebius Loop'.