Yah, it was in Episode 46, during Season Two, that "The Gamesters of Triskelion" aired. In it, three disembodied brains entertained themselves by making more corporeal beings fight each other in gladatorial surroundings. The people/creatures who ran the planet on which these games occurred were called Thralls, and all were controlled by "The Providers" -- the three brains -- through choke collars around their necks which could be activated by Provider brain power ... or something like that.