5. The X-Files 1998 Film/Mulder Leaves Post Season 7
This is actually quite an ironic one, there is an episode of X Files called Jump the Shark and although this actually isnt the jump the shark moment it almost feels like the writers were acknowledging that they are on borrowed time with this franchise. Again, this is not a franchise I was ever a big fan of but it did have a cult following and indeed people seem to think that there was a turning point which the show never recovered from. The first bad seed was the first motion picture; whilst it has received a lot of praise from critics it had a mixed reception from the fans. This bad seed then began to take root and before you knew it this bad seed grew into a mutant shark weed plant (New comic book coming this fall!) David Duchovny plays the iconic Fox Mulder character in this franchise, a character who arguably is irreplaceable (probably more so than Scully, Gillian Andersons character), ultimately though you seem to find the more irreplaceable the character, the higher the likelihood that they will leave the show; whether it be for fear of typecasting, egos of the actor, egos of the studio or contract disputes, in Davids case it was the latter and thus Season 7 became the last season he featured prominently in the line up. He continued to make the odd appearance in Season 8 and made a return for the franchise finale in Season 9 but it was clear that fans felt there was too much of a void left by Mulders absence next to Scully; I mean they have become one of the most famous pairings from the least 20 years of TV. Fox tried to keep the program going but ultimately something was lost with the absence of David Duchovny and the Evil Mutant Shark Weed Plant ended up devouring the franchise. (Side note: I am aware that I could be in breach of my own guidelines because another X Files film was made since the series concluded and there may be a potential third in the mix, however I am not counting films made after cancellation or spin offs for that matter either, plus the second film was apparently worse and the third isnt even off the ground yet, it may not even get that far.)