15 of 18
Abruptly departed: Gale Harold, second from right
Played: FBI Agent Graham Kelton
Lasted: Seven episodes (eight if you count a shot of his corpse) in 2006
Why he left: The "Queer as Folk" star had a loyal fan following, but it wasn't big enough to make "Vanished" a ratings hit. In an attempt to shake things up (amid rumors of on-set clashes) the producers let the star go just before the show took a hiatus for baseball playoffs. The series was canceled two episodes later.
How it went down on air: While attempting to unravel the vast conspiracy surrounding the kidnapping of a senator's wife, Kelton is gunned down by the same mysterious forces he was tracking.