The "But I'm Ironman"/"But I'm Batman" Game

Playing field: Inside automobile, preferably during car trip.
Players: Two siblings, backseat; parent or friend's parent driving.
Best played: Immediately before The Super Secret "But I'm Ironman"/"But I'm Batman" Game.

Each sibling picks one side of titled argument. One begins by stating: "But I'm Ironman!" The other retorts with, "But I'm Batman!" Continue in this fashion until driver pulls over and threatens physical harm if the game is ever, ever, ever played again.

Game log:

Shirley: Make room. I want to stretch my legs.
Leo: No!
Shirley: But I'm Ironman.
Leo: But I'm Batman.
Shirley: But I'm Ironman!
Leo: But I'm Batman!
Shirley: But I'm Ironman!
Leo: But I'm Batman!
Driver: Shut up! Shut up! Shut up!
Shirley: But I'm Ironman...
Leo: But I'm Batman...
Shirley: But...I'm Ironman.
Leo: But, I'm...Batman.
Driver: Didn't I just say, "shut up!"
Shirley: (crying) But I'm Ironman!
Leo: (outdoor voice) But I'm Batman!
Shirley: (falsetto) But I'm Ironman!
Leo: (Val Kilmer-ish) But I'm Batman!
Shirley: (sung to the melody of "Iron Man" by Black Sabbath) But I'm Ironman!
Leo: (screeching) But I'm Batman!
Shirley: (stretching legs) But I'm Ironman!
Leo: (like a robot) But I'm Batman!
Driver: (pulling over to the shoulder of Rte 3) Ironman, Batman: shut it up! (to passenger) Elaine, what's the hell's wrong with your kids?