While studying the orb that captured David, Cary says to himself "it's advanced, but not Shi'ar." This is a reference to the Shi'ar Empire in Marvel comics. They are an advanced alien race that uses technology to conquer worlds, and frequent enemies of the X-Men.
One of The most brilliant hours of tv I've ever seen. It's like Twin Peaks without the confusion and alienation. And the music is the best soundtrack ever.