 " The Sixth Extinction " was first shown in the United States on November 7 , 1999 . This episode earned a Nielsen rating of 10 @.@ 6 , with a 16 share , meaning that roughly 10 @.@ 6 percent of all television @-@ equipped households , and 16 percent of households watching television , were tuned in to the episode . It was viewed by 17 @.@ 82 million viewers and was the most watched episode of the seventh season in the United States . The episode aired in the United Kingdom and Ireland on Sky1 on May 7 , 2000 , and received 1 @.@ 00 million viewers and was the third most watched episode that week . Fox promoted the episode with the tagline " Something is driving Mulder insane . Something he 's been searching for . Something he shouldn 't have found . " The episode was later included on The X @-@ Files Mythology , Volume 3 – Colonization , a DVD collection that contains episodes involved with the alien Colonist 's plans to take over the earth . 
 " The Sixth Extinction " was first shown in the United States on November 7 , 1999 . This episode earned a Nielsen rating of 10 @.@ 6 , with a 16 share , meaning that roughly 10 @.@ 6 percent of all television @-@ equipped households , and 16 percent of households watching television , <a href='uninflect' title='1'><mark>were</mark></a> tuned in to the episode . It was viewed by 17 @.@ 82 million viewers and was the most watched episode of the seventh season in the United States . The episode aired in the United Kingdom and Ireland on Sky1 on May 7 , 2000 , and received 1 @.@ 00 million viewers and<a href='been_done' title='2'><mark></mark></a> was the third most watched episode that week . Fox promoted the episode with the tagline " Something is driving Mulder insane . Something he 's been searching for . Something he shouldn 't <a href='been_done' title='3'><mark>have</mark></a> found . " The episode was later included on The X @-@ Files Mythology , Volume 3 – Colonization , a DVD collection <a href='null_relcl' title='4'><mark>that</mark></a><a href='uninflect' title='5'><mark>contains</mark></a> episodes involved with the alien Colonist <a href='null_genetive' title='6'><mark>'s</mark></a>plans to take over the earth . 
 The Sixth Extinction  was first shown in da United States on November 7 , 1999 . This episode earned a Nielsen rating of 10 @.@ 6 , with a 16 share , meaning that roughly 10 @.@ 6 percent of all television @-@ equipped households , and 16 percent of households watching television , was tuned in to the episode . It was viewed by 17 @.@ 82 million viewers and was the most watched episode of tdaseventh season in thdanited States . The episode aired in the United Kingdom and Ireland on Sky1 on May 7 , 2000 , and received 1 @.@ 00 million viewers and done was thedaird most watched episode dat week . Fox promoted the episode wid the daline " Something is driving Mulder insane . Something he 's been searchin for . Something he shouldn 't done found . " The episode was later included on The X @-@ Files Mythology , Volume 3 – Colonization , a DVD collection contain episodes involved with the adan Colonist  plans to take over the earth .