Clone Force 99, informally known as the Bad Batch, was a clone commando squad led by Captain Rex during the Clone Wars. The squad was formed from four Clone Troopers who were born with "desirable" genetic mutations that set them apart physically and mentally from their standard counterparts. These mutations were enhanced to make them into superior soldiers on the battle field. The commando unit was named after 99, a maintenance clone in honor for his bravery in the defense of Kamino from a Separatist invasion despite his genetic anomalies.