Gravity Falls (found Comic Con 2012 promo of Disney Channel animated mystery comedy series; 2012)
From The Lost Media Wiki
Logo.
Status: Lost
At the 2012 Comic Con, several then-new shows and episodes of shows were being announced, with some even having sneak peaks, such as Gravity Falls. This preview was once on Youtube, but it was taken down, likely due to copyright infringement. It has not been published officially in any way, however.
The promo reportedly featured clips from the first group of episodes (up to "Irrational Treasure") as well as a slightly different version of Dipper's cold open.