"The Mystery of Chopper Base" Episode Guide | Star Wars Rebels - S2 E20

A remote world of rock, the rebellion sought to establish a secret base on Atollon. But the planet was not as devoid of life as originally believed. Giant, multi-legged, spider-like creatures called krykna lived below the surface. They were aggressive beasts and relentlessly attacked the rebels. Eventually, the freedom fighters were able to repel the krykna using sensor markers and could keep their new home base.

Larger than fully-grown humans, krykna were giant, spider-like creatures native to the remote world of Atollon. Predominantly white, they had six powerful legs, eyes around their head, and a blaster-resistant hide, making them fierce hunters. They often take their prey into an underground hive, where they cocoon their victims. Krykna attacked the rebels looking to establish a base on Atollon but the creatures were repelled by sensor markers.

One of the rebellion's pilots, Lieutenant Dicer was among the first to try to set up a base on Atollon. Unfortunately for Dicer, the world was not as desolate as believed -- huge spider-like creatures called krykna lived below the surface. After the krykna attacked, all that was left of Dicer was her helmet.

On the barren world of Atollon, few lifeforms survived. Among them, however, were the dokma: small, timid creatures that featured an outer protective shell. The larger krykna, which were spider-like hunters, often ate the dokma, proving Atollon to be a dangerous place no matter how desolate.

Convorees (plural for convor) were small, flying creatures found from world to world. They had two eyes, two feathered wings, and a beak, feeding mostly on insects and small rodents.

Rex once served the Republic on the frontlines during the Clone Wars, taking orders from Anakin Skywalker and Ahsoka Tano as first a captain and later a commander. He viewed military service as an honor, and his loyalty to the Republic and his Jedi Generals was absolute. But when Order 66 was executed, it was Ahsoka who helped to free Rex from the programming of his inhibitor chip. At the dawn of the Empire, Rex has escaped with his life but is considered killed-in-action in the eyes of the new regime. That allows him to operate in the shadows and help any clone brothers who remain separate from the Imperial ranks.