A movie or television show character who is completely expendable and whose only purpose on the show is to die. The character's death is usually used to demonstrate the gravity of the situation that the main characters will shortly find themselves in. See also redshirt; the two terms are synonymous, but this term is more commonly used within the entertainment industry as an inside joke.
"Look out for that lava, Crewman Number Six!!"
"I'm just "Crewman Number Six." I'm expendable. I'm the guy in the episode who dies to prove how serious the situation is. I've gotta get outta here." - Sam Rockwell as "Guy Fleegman" in "Galaxy Quest" (1999)