The Gumbus is a "specter" that was supposedly haunting the Stock n' Stop supermarket. However, it was ultimately revealed to be a robot created by Baxter Stockboy.
The Gumbus, in its spectral disguise, is a levitating ghost with light blue skin, bright pink eyes, a head shaped like a milk carton, and a ghostly tail instead of legs. Its attire consists of blue overalls and chains wrapped around its neck.
In its true form, the Gumbus is a large robot with turquoise-gray armor, bright pink eyes, and sharp claw-like fingers. The robot also has disproportionately small legs, which may not be functional, as it is suspended from the ceiling by a wire.
The Gumbus was supposedly a ghost that haunted a supermarket owned by Baxter Stockboy's parents. It first "kidnapped" Baxter and transferred his soul into a turkey carcass. The Gumbus later terrorized Leo, Mikey, and April. However, it was unmasked by Mikey and was revealed to be a robot controlled by Baxter. The trio also learned that Baxter made up the legend of the Gumbus in order to have people "subscribe and donate".
Baxter Stockboy: Baxter built the Gumbus.