Brainwashing Movies?

So this is actually for something I’m writing, but I wanted my protagonist to compare someone to a person in a movie who’s been mind-controlled (or cloned or any other method) and suddenly starts acting nicer or more compliant. In the story, his friend starts acting way too nice out of no where and my protagonist is known to make everything into a pop culture or movie reference.

As I started to write this dialogue, I thought I knew a million movies with this plot, but I suddenly couldn’t think of a single one. Trying to research it online only got the opposite, of characters getting progressively crazier.

Thanks to anyone that can help!

P.S. Bonus points if it’s something that came out pre-2009, as that’s around when my story takes place. And doesn’t necessarily have to be popular as my protagonist loves movies but would be better if my readers could recognise it