Dipper and Mabel started to argue about who was taller. it started to get pretty heated with them yelling and screaming surprising that their Grunkle stan didn't hear it nor did Wendy or Soos. in a rage, Mabel grabbed the shrink device that Gidien made which was just a flashlight with a weird crystal where the bulb would be. She shot Dipper with it shrinking him down to practically microscopic. he was still visible but just barely. She giggles "Hehe, looks who's taller now." she picks him up and lands him in her ballet flats.