Jack is a large pumpkin who lives in Bumblyburg. He only appears in "Larry-Boy and the Rumor Weed" as a member of the Library. He believed in the rumors about Alfred being a robot, but soon realized it was a lie. He was one of the people who blocked Alfred's path to escape, before he knew the rumor wasn't true about him being a robot.
Jack is a large orange pumpkin. He has a big green stem and a curly leaf. His eyes and nose are quite small, due to his body being so big.
- Himself in "Larry-Boy and the Rumor Weed" (cameo)