Castle: If you could be any comic book character in the world, who would you be?
Castle: Ah, a ruthless assassin who hides from her emotions.
Beckett: No, maybe it's because she's got badass ninja skills. What about you? Iron Man? Spider-Man? No, wait. I know. Annoying man.
Castle: Try billionaire industrialist Bruce Wayne, a.k.a. the Dark Knight. He's brooding, he's handsome, and he has all the coolest toys.
Beckett: Wow. Digging deep on that one.