Serenity (2005)
Serenity is the rare feature film made to give a canceled television series a proper conclusion. Joss Whedon wrote and directed.
Nathan Fillion played Mal Reynolds in Firefly, cancelled after fourteen episodes, and the audience response was substantial enough to produce a feature film, Serenity, three years later.
Slither gave him a horror comedy lead for James Gunn, and he has appeared in most of Gunn’s films since in small roles. Castle and The Rookie gave him long television leads, and he voices Cayde-6 in Destiny.