Ernesto is minor antagonist in Gravity Falls. He is a residential figure from Mabelland, who was imagined to be the father of Soos.
He appears in "Weirdmageddon 2: Escape From Reality" when Mabel explains Dipper, Soos and Wendy what is Mabeland, she has a surprise prepared for each one of them. For Wendy, she has her friends Lee, Nate, Tambry and Thompson in a monster truck inviting her to do pranks. After Wendy leaves Dipper and Soos, Soos promises Dipper that "there's nothing in that world that could break him from their mission, but then Ernesto enters, introduces himself and invites him to play catch, to what Soos replies that "he's] perfect" and that "even if it is all a dream, he has to play just one game, leavig Dipper alone with Mabel.
He later appears in Mabeland court when Dipper is tried for mentioning reality. When Dipper and Mabel reconcile in court, and Mabel decides to return to reality, Ernesto, along with the other imaginary creatures, turn against Mabel and chase down the twins, Wendy, and Soos to prevent them from escaping.