Trivia: Castle's Halloween costume is of Malcolm Reynolds, played by Nathan Fillion in the short-lived TV show "Firefly." Alexis asks him: "Didn't you wear that like five years ago?" Serenity, the film based on Firefly, was released 5 years before this episode aired.Cubs Fan
Trivia: In this episode, Castle says the words "My partner is crazy and may start firing at any moment" in Chinese. Beckett then asks him "Semester abroad?", to which he replies "Nah, a TV show I used to love". This is a reference to Firefly, a TV show starring Nathan Fillion in which characters occasionally spoke in Chinese.THGhost
Beckett: Murdered Medina just to boost ticket sales? No, that would make this Scooby-Doo... And I'm not Velma.
Castle: Velma, you kidding? You're Daphne... You're hot, smart, not aggressively brainy, but long legs, short skirt...
Castle: Got it.