Each Jeby had three heads and a scaly, white body covered in pink or red spots. Located at the lateral sides of the body were six tentacles, for a total of twelve. Individuals stood on four legs. A Jeby's spots had a tendency to detach when an individual laughed, but they could be sucked back up by the Jeby's tentacles. These manipulators could also be used to handle other objects. Although the tentacles were primarily white, each featured a pink or red band at the midpoint and the tip. The Jeby's legs, while also white, were banded pink and red.
The three Jeby necks originated from a single point on the body and were segmented into two different colors at their midpoints—for example, one neck could be red and yellow, while another was green and light green. The Jeby face featured two black eyes, a nose, and a mouth. Atop each of these circular heads, a Jeby sported a single black hair, which stood straight up.
Jeby were prone to mirth—their laughter caused the pink spots covering their body to fall off. As a result, a Jeby had to recollect their lost body parts with his or her tentacles and restore them to the body. When detached, the spots of the Jeby littered the surface of their homeworld, Rainboh.
The Jeby dwelled on the rainbow-colored planet of Rainboh, which was located within the Hapan Rim Worlds of the Hapes Cluster. This area of space was presumed to have been constructed by a group of beings known as the Celestials. Although the cluster was reached by outsiders between 20,000 and 5000 BBY, it remained cut off from the galaxy at large from 3100 BBY until 8 ABY.
Seven-year-old Paul Rice created the Jeby through the "Design An Alien" competition held in Star Wars Galaxy magazine, which asked Star Wars fans to create completely new alien creatures inspired by the original Star Wars trilogy. The contest was initiated in Star Wars Galaxy Magazine 3, which inspired Rice's first-grade teacher at a Cleveland Heights primary school to use it as an art project for the students. Star Wars Galaxy received several entries from the class, but Rice's was the only one published in Star Wars Galaxy Magazine 7 (1996). The Jeby came under the "honorable mentions" section of the "under 16" subdivision. Rice's description of the Jeby leaves the beings' sentience ambiguous.
Star Wars continuity editor Leland Chee has stated that published "Design an Alien" material is considered canon. The planet Rainboh, which was created in Rice's entry, is included in The Essential Atlas (2009), by Jason Fry and Daniel Wallace.