 " The Sixth Extinction " helped to explore new aspects of the series ' overarching mythology and was the second episode in a trilogy of episodes featuring Mulder 's severe reaction to the appearance of an alien artifact . The episode was written due to series creator Chris Carter 's fascination with the possibility that extraterrestrials were involved in the great extinctions that had happened millions of years ago . 
 " The Sixth Extinction " helped to explore new aspects of the series <a href='null_genetive' title='1'><mark>'</mark></a>overarching mythology and was the second episode in a trilogy of episodes featuring Mulder <a href='null_genetive' title='2'><mark>'s</mark></a>severe reaction to the appearance of an alien artifact . The episode was written due to series creator Chris Carter <a href='null_genetive' title='3'><mark>'s</mark></a>fascination with the possibility that extraterrestrials <a href='uninflect' title='4'><mark>were</mark></a> involved in the great extinctions <a href='null_relcl' title='5'><mark>that</mark></a><a href='been_done' title='6'><mark>had</mark></a> happened millions of years ago . 
 The Sixth Extinction  helped to explore new aspects of da series  overarching mythology and was the second episode in a trilogy of episodes featuring Mulder  severe reaction to tdaappearance of an alien artifact . The episode was written due to series creator Chris Carter  fascination w the possibility that extraterrestrials was involved in thdareat extinctions done happened millions of years ago .