The Joopa became the symbol on Zeb's chest plate.
Hunt on Seelos
During the reign of the Empire, the crew of the Ghost agreed to help the clones, Rex, Wolffe, and Gregor hunt Big Bongo, an enormous Joopa. While the Lasat known as Zeb acted as bait for Big Bongo, it swallowed him whole, causing the clones and the rebels to chase after the creature, together, Kanan Jarrus and Ezra Bridger managed to bring the beast up to the surface, while Rex shot it with a blaster bolt. The corpse was later dropped by Gregor to run away from the AT-AT's that were hunting them.
The Joopa was a worm-like creature with naturally armored skin. It had pairs of red, bulbous eyes with a long red tongue and a large body. Joopa were known to mostly live under the ground of Seelos, and only surfaced to hunt for food.
Joopa were known as carnivores and would eat anything with meat, swallowing them whole. Joopa were also fond of Lasats, when they could get them.