Clone Force 99, unofficially known as the "Bad Batch" and designated as Experimental Unit Clone Force 99, was a Clone Commando Special Forces squad that was active during the Clone Wars. The squad initially consisted of four Clone Commandos that were designed with genetic mutations and led by Clone Sergeant CT-9901 "Hunter" with enhanced sensory abilities. Other members of the squad included CT-9902 "Wrecker" a reckless brawler with an enhanced muscular form; CT-9903 "Tech" who possessed enhanced mental capacity and intelligence; and CT-9904 "Crosshair" who was enhanced with keen eyesight and marksmanship that allowed him to excel in long-distance firefights.
Following the crucial Battle of Anaxes, Advanced Recon Commando (ARC) Clone Corporal CT-1409 "Echo" joined the unit.
Most of the members' mutations and the ordeal Echo suffered prior to joining caused their inhibitor chips to have less effect, meaning Clone Force 99 was able to disobey Order 66, at least it seemed at first, while they were fighting in the Conquest of Kaller. Hunter helped Jedi Padawan Caleb Dume escape the "Regular Clones" by lying about his death. However, unlike the rest of the squadron, Crosshair was affected by his chip and attempted to kill Dume during the incident, though the team was unaware of the cause to his change in behavior.
Upon returning to Kamino in the aftermath of Order 66, as the Galactic Republic became the Galactic Empire, the Bad Batch's loyalty was questioned by Admiral Wilhuff Tarkin, whom arrived to evaluate the need for Clones to continue their service with the Empire. The Admiral sent them to Onderon under the pretext of terminating Separatist remnants. After the squad disobeyed orders to kill what was discovered to be civilians and former Republic fighters during the mission, all of the squad's members, save Crosshair, deserted from the Empire, taking with them Omega, a young experimental female Clone they met on Kamino. Now fugitives from the Empire, they eventually come to work as mercenaries for the information broker and female Trandoshan "Cid" in the early Imperial Era.
After returning from a mission to secure a Tactical Droid from a decommissioning center on Corellia, the Batch and Omega were sought out and found by Clone Captain CT-7567 "Rex" in Cid's Parlor upon Ord Mantell. It was at this time that the real nature of their chips had been discovered and further explained. Rex declared it was imperative the chips be removed before they activated, knowing it was only a matter of time before they succumbed to the same fate as he himself had once endured.
The Captain led them to the junk planet of Bracca where they successfully removed their chips inside a former Jedi Cruiser's medical bay. However, due to many blunt force blows to the head, Wrecker's chip had activated just before being sedated for surgery to remove his inhibitor and the massive Clone attacked his companions with the intent to kill, claiming them as traitors. Luckily, he was stunned by Captain Rex before he could kill anyone and underwent the chip removal without further incident, and the remaining members of the squadron were quick to follow in liberation from the control chips.
