In "Batman", there is a scene where Jack Palance is convincing Jack Nicholson to take on the task that will ultimately lead to the creation of The Joker. Palance grabs Nicholson's shoulders and says, "...because you're..." and then he makes this weird inhaling hiss sound, "...my number one."
Something always struck me as bizarre about that scene and it took me years to figure it out. Palance is explicitly stating that Nicholson is his toadie. And the latter's actions prove it. Why is that strange? Well, how many times in his career has Nicholson taken on that role? He's always the dominant character and never answers to anyone other than his arrogant self. We're so used to seeing the "Cuckoo's Nest" Jack, the "Shining" Jack, even the "As Good as it Gets" Jack that you just know he can't remain sebverient for long. In this case we're right, and it only takes immersion in acid for the watershed moment to occur.