During the Clone Wars, Wrecker was a member of the Bad Batch, an elite group of clones called in for special missions for the Republic. On one occasion, he and his fellow troopers were sent to infiltrate a Separatist Cyber Center and learn valuable intel about the battle on Anaxes.
On Skako Minor, Clone Force 99 helped Anakin Skywalker and Clone Captain Rex get behind enemy lines to rescue the clone called Echo, who was previously thought lost in the escape from the Citadel. After the rescue and the defeat of the enemy at the Battle of Anaxes, Skywalker gifted Wrecker with a detonator to blow up the Separatist Dreadnought -- one of the happiest days in the clone's life.
But at the end of the war, the execution of Order 66 put Wrecker and the rest of the Bad Batch in a difficult position. They did not respond to the inhibitor chip in the same way as their clone brothers, and on Kaller they even allowed a young Padawan named Caleb Dume to escape -- despite the directive to kill all Jedi for treason. Back on Kamino, Wrecker and his brothers were tested by the Empire, which used live ammunition to assess their battle prowess in what was intended to be a training simulation.
After an Imperial mission to eliminate an insurgency of Separatist droids on Onderon -- only to find organic beings just trying to survive -- Wrecker and his brothers defected from the new Empire alongside a child called Omega, who was a mutated clone like the rest of the Bad Batch. However, Crosshair remained behind to serve the Emperor and Admiral Tarkin.
As fugitives, Wrecker and Clone Force 99 found work off the books with Cid, a Trandoshan who had been an ally of the Jedi during the war. On a job at Old Ord Mantell City, Wrecker's strength was the only thing capable of subduing a rampaging adolescent rancor called Muchi whom the Bad Batch was sent to rescue.
But when Wrecker suffered a head injury during a mission to a droid decommissioning facility, he began to suffer from debilitating headaches accompanied by muttering, "Good soldiers..." Soon after, Clone Captain Rex reunited with the Bad Batch and astutely diagnosed the ticking timebomb in Wrecker's head -- the inhibitor chip.
Rex and Clone Force 99 travelled to Bracca where a scrapyard provided the medical tech needed to remove the chips. Just before the first operation, Wrecker lost control of himself, firing his blaster at his friends and even stalking Omega who desperately tried to calm her friend. Fortunately, Rex subdued Wrecker with a stun jolt and the chip was removed successfully.
Clone Force 99 ultimately ended up back on their homeworld of Kamino. Together, Crosshair and the rest of the Batch witnessed the planet's destruction by the order of Vice Admiral Rampart and his Star Destroyers. The Bad Batch were presumed dead, but together they escaped a watery grave, leaving Crosshair behind when he refused to join them once more.