User blog comment:The Dark Lord of the Sith/Reviving "The Clone Wars" - Episode 1, "The Bad Batch"/@comment-3298705-20141101171358/@comment-108.198.29.228-20141117004333

What I'm referring to is the "tumor" inside the head of each clone, inserted by the Kamonians. It caused them to automatically follow orders such as Order 65 and Order 66.