X² - Double X

Imdb claims this is a "series" of music videos, but I only was able to find a single official music video, done in the year 1993, which feels pretty much like a pilot (Or if you prefer, a teaser preview) for the 1996 movie.

This animation is nicely done, though it could be a bit confusing and random for those viewers who are not familiar with the plot of this comic series. Still, a pretty interesting watch for CLAMP fans.