As anyone who's been on the Internet for the last week knows, Nathan Fillion and Firefly are still attached at the hip. And even though he's got a hit crime procedural on ABC, the once and future (if he has his way) Mal Reynolds can't help but sneak his love for Joss Whedon's cult hit into his new gig.

The references started in Castle's second season, after the fear of another Fillion show not making it past a first season faded. Last night's episode added another to the ever-increasing list.





Two by two, hands of blue

Castle episode: "Fool Me Once," season two, episode four

Firefly episode referenced: "The Train Job." When River Tam—the preternaturally gifted victim of government torture and bioengineering—senses the Alliance agents coming to get her, she just keeps saying "Two by two, hands of blue," referring to their number and the gloves they'd be wearing.





Space Cowboy

Castle episode: "Vampire Weekend," season two, episode six

Firefly episode referenced: Well, the whole show, really.





"Yeah, you better run."

Castle episode: "The Mistress Always Spanks Twice," season two, episode 16

Firefly episode referenced: "Trash." Part of Mal's grand plan to double-cross Saffron (Christina Hendricks), the con woman who nearly made off with Serenity, seemed to involve him being left, naked, in the middle of the desert. As Saffron flies off in his shuttle, these are his parting words.





"I was aiming for his head."

Castle episode: "Boom!" season two, episode 18

Firefly episode referenced: "The Train Job," where Jayne—zonked out of his gourd—shoots a Niska's implacable henchman in the leg, saving Mal's life.





"Just a TV show I used to love."

Castle episode: "Close Encounters of the Murderous Kind," season three, episode 9

Firefly episode referenced: The Sino-American nature of Firefly's future world saw to it that Chinese was a second language to the characters.





"I like to feel shiny."

Castle episode: "Lucky Stiff," season three, episode 14

Firefly episode referenced: "Shiny" was a Whedonism that cropped up throughout the series, used to refer to things that were better than all right—a general state of blissful contentment.





"You haven't heard of the Serenity?"

Castle episode: "Setup," season three, episode 16

Firefly episode referenced: Again, less a specific episode than the entire series, as well as the feature-film sequel—which was named after Mal's trusty ship, the Serenity.