The Undead are menacing paranormal creatures that were summoned in Gravity Falls.
Originally, Journal 3 stated that the Undead has no weakness, but written in invisible ink, it states that it is possible to defeat them with a three-point harmony that can shatter their skulls and return them to dead. As zombies, the Undead can infect the living with a bite and transform them into other zombies. Due to their pale skin and bad attitudes, they are often mistaken for teenagers. They seem to have a hunger for brains.
According to the "Creature #6" next to the species' name, they are implied to be the sixth creature to be written about in the book.
There is a cure for those who were infected by the Undead's bite which involves cinnamon and formaldehyde.
Role in the series
The Undead was mentioned in the first episode "Tourist Trapped", where they were described to look a bit like teenage boys.
In "Scary-oke", Dipper Pines accidentally summons a hoard of them to prove the Federal Agents that his Journal is real. Several of the zombies drag the agents away into the woods before attacking the Mystery Shack and infect Soos, turning him into one of their own. When the zombies' weakness is discovered, Dipper, Mabel, and Grunkle Stan sing a court song and destroy the zombie hoard.
In "Weirdmageddon Part 3: Take Back the Falls", several zombies, including the late Mayor of Gravity Falls, try to rise from the graveyard behind the Valentino family's funeral home, but the Valentio couple suppress them back into their graves.