[Castle has arrived late to a crime scene]
Esposito: Yeah, it's too bad, too. Your kind of case, bro'.
Castle: Yeah?
Ryan: Yeah, body was found down that manhole over there. Half eaten.
Castle: Eaten?
Ryan: Yeah, it was covered in some kind of green slime.
Castle: Whoa...
Esposito: Yeah, it was creepy. It's as if someone or some thing is down there.
Castle: [Catching on] Ha, that's... okay. Very funny. Great. [To Beckett] Was there a body down the manhole?
Beckett: Yeah.
Castle: Okay, thank you. An adult.
Beckett: Yeah, you should have seen what else was down there. Two metal canisters with bio-hazard stickers and yellow powder inside of them.
Castle: You opened the... [the detectives smirk] Alright. Will someone please tell me what's really going on here?
Ryan: We're gonna check nearby trash cans for the murder weapon.
Castle: What was the murder weapon, by the way?
Ryan: Some kind of death ray.
Esposito: Turns your insides out.

[Castle relates a traumatizing childhood experience that spurred him to become a mystery writer]
Castle: It must have just happened, because the tide hadn't washed away the blood. We had just played hide-and-go-seek the day before.
Beckett: What happened to him?
Castle: They never found out.
Beckett: I'm so sorry, Castle. [he smirks] ... you made that up?
Castle: It's what I do!
Beckett: You know what? You are so getting it for that one!

[Hans finds out Castle is not the person he was supposed to meet and grabs his shirt]
Beckett: NYPD! Hands up! [Castle puts his hands up] Not you Castle!
Castle: Right.

[M.E. Perlmutter eats his lunch on an examination table in the morgue]
Castle: Are you sure it's sanitary to be eating here?
Perlmutter: Do you know the strength of the disinfectants we use here? This is the cleanest room in the city. [offers his sandwich to Castle]
Castle: I couldn't.
Perlmutter: Homemade.
Castle: I couldn't.