Favorite movie character not in the books.

[The Only Real Estel]

I like the old Hobbit who is constantly sweeping the path outside his home. I know he's not really an invention per se, but still...

Ah, that's a good one. And while we're on the topic of hobbits who probably aren't exactly invented, I'll cast one of my votes for the hobbit that interrupts a promising moment to grab a cupcake & stuff it in his mouth in FotR .
I'd also have to say Lurtz, if only because he's the only guy I know that can get both his right arm & his head chopped off without losing a drop of blood .