Well there is Count Chocula and Frankenberry, Fruit Brute... Or how about THE PHANTOM CREEPS? Maybe it's just because I grew up thinking that robot would play a bigger part in it (And I've still only seen one or two chapters, and the dreadful feature film version.), but I guess that was as close as we ever got to a horror serial. It's got Lugosi and Van Sloan in it to boot!

-Clark