Big Bongo was an enormous joopa that resided beneath the surface of Seelos, a planet situated in the Outer Rim Territories. After his days in the military were over, Gregor, a human clone who previously fought for the Galactic Republic, relocated to Seelos. He lived inside a modified AT-TE walker alongside his companions, Rex and Wolffe. As time passed, Gregor developed an intense desire to capture Big Bongo. Upon the Spectres’ arrival on Seelos, Gregor persuaded Garazeb Orrelios, one of their members, to act as lure for the massive joopa, as it was believed to have a fondness for Lasat flesh. Kanan Jarrus, a Jedi hiding from the Empire, along with his Padawan Ezra Bridger, who were also Spectres, employed electrostaffs to transmit energy pulses along a laser path below ground. When Big Bongo emerged from the earth, Rex killed it with a precise shot from the AT-TE's primary weapon. The clones transported the dead creature's body attached to the side of their walker for a while. Nevertheless, when the Galactic Empire initiated an assault, Gregor and his friends had to discard it to improve their speed and maneuverability.