Great Scott! When the "Back to the Future" trilogy is re-released on Blu-ray and DVD for its 30th anniversary, the new commemorative box sets will include a new short featuring Christopher Lloyd as Doc Brown.
In a brief teaser trailer titled "Doc Brown Saves the World," Brown travels to October 21, 2015 in his Delorean. After he sets up the audio visual tracking, the teaser cuts to the classic titular text, which reads "To be continued..." The short will only be available on the 30th Anniversary Blu-ray/DVD trilogy sets.
Coincidentally, the 30th Anniversary "Back to the Future" Blu-ray/DVD trilogy sets will be released on October 21.