(Another possible story that could have took Piceae Cipher place)
Dipper and Mabel were chased by a monster, and Dipper was about to die, until someone came to his aid.
Now his been transcended into a new being called a reaper.
Dipper and Mabel get more than they bargained for when Mabel accidentally turns Grunkle Stan, Soos, and Wendy into 12 year olds! Now when they find themselves in an almost Reverse like Gravity Falls, they must try to set things right again. Get ready to follow Dipper, Mabel, their 12 year old Grunkle, Soos, Wendy, and...... a human Bill Cipher!?