 The television series Castle , where Fillion plays the lead character Richard Castle , has made ongoing homages to Firefly . Castle has props from Firefly as decorative items in his home , has dressed up as a " space cowboy " for Halloween ( " You wore that five years ago , " cracked his daughter ) , speaks Chinese that he learned from " a TV show [ he ] loved " , and has made rapid " two @-@ by @-@ two " finger motions while wearing blue surgical gloves . He has been humorously asked if he has ever heard of a spa known as " Serenity " , and Firefly catchphrases such as " shiny " , " special hell " and " I was aiming for the head " have been used as punchlines during various dramatic scenes in Castle . He has worked a murder case at a science fiction convention with suspects being the cast of a long @-@ cancelled space opera that only ran for a season , and has had incidental interaction with people portrayed by Firefly cast members . 
