In the year 18 BBY, Ciddarin Scaleback tasked the group known as the Bad Batch with a salvage operation. Their mission: to recover valuable materials from a transport that had crashed on the surface of Silla.
Following the Galactic Empire's devastating bombardment and destruction of the Kaminoan cloning facilities and their cities, the Empire initiated its own cloning program. This program was based within a facility located on Mount Tantiss on the planet of Wayland. Despite lacking the refined techniques of the Kaminoans, the Imperial cloning program, under the direction of Emperor Palpatine, undertook various cloning projects. Some months after the destruction of Kamino, the Empire successfully cloned a Zillo Beast using DNA obtained from the very creature that had attacked Coruscant some years prior. This juvenile clone was being transported aboard an Imperial vessel from an undisclosed location to Mount Tantiss when it managed to escape its confinement and assault the ship's crew. The creature severely damaged the ship, forcing it out of hyperspace, and then pursued a surviving Imperial clone commando through the ship's corridors. Just as the commando prepared to defend himself with an electrostaff, the Zillo Beast ambushed him, dragging him into the ship's ceiling shafts with a scream, where it killed and consumed him. The crippled ship subsequently crash-landed on the nearby planet of Silla, its presence noted by the residents of a close village.
Ciddarin Scaleback, an information broker, eventually discovered the wreckage's existence. She offered the Bad Batch a deal: scout the ship for valuable cargo in exchange for 50% of the profits. Despite their reservations about working with Cid again after a previous betrayal, the squad ultimately agreed to the assignment. Meanwhile, Royce Hemlock, the doctor overseeing the Imperial facility on Mount Tantiss, received news of Transport 904's crash and immediately dispatched a recovery team to retrieve the ship's cargo.
The Bad Batch arrived on Silla before the Imperials and began their reconnaissance of the Transport 904 wreckage. As they navigated the ruined vessel, the clone mercenaries gradually sensed that they were not alone, that something was alive and hunting them. After further exploration, the juvenile Zillo Beast, which had survived the crash, ambushed the group. Following a brief skirmish with the rogue clones, the beast fled the ship, heading towards a nearby village with the intention of feeding on its power grid. Hunter, the squad's leader, pursued the creature along with Wrecker aboard their ship, the Marauder, while Tech and Omega reentered Transport 904 to gather more information about the beast. In the meantime, the juvenile creature reached the power grid and consumed its energy, triggering a rapid metamorphosis into its massive adult form.
At the same time, a fleet of Imperial Venator-class Star Destroyers appeared above Silla and deployed numerous LAAT/i gunships and V-wing starfighters. These forces rapidly descended to the planet's surface, followed by a science vessel equipped with a NNJ-40 "Thunderbolt" long-range ion cannon. Upon locating the Zillo Beast, the Imperials divided their forces. The V-wings moved to destroy the remnants of Transport 904, while the LAAT/i gunships drove off the Bad Batch and contained the Zillo Beast. After incapacitating the Zillo Beast with the ion cannon, they captured it and placed it in stasis aboard the science vessel. The Bad Batch, meanwhile, were forced to flee the planet after a short aerial chase. Simultaneously, three Rho-class transport shuttles deployed clone commandos into the village near the battle, with orders to secure the area and round up any witnesses to the cloned Zillo Beast.
The Bad Batch managed to escape into hyperspace before the Imperials could intercept them, carrying with them secret information extracted from Transport 904. After reviewing the data and uncovering Palpatine's plans to exploit cloning technology acquired from Kamino for his own sinister purposes, Hunter decided to send the information to Captain Rex, who was leading a small but organized resistance against the Empire. Back on Silla, the Imperial clone commandos rounded up the village's residents and transported them off-world to an unknown fate.