 " Sanguinarium " is the sixth episode of the fourth season of the American science fiction television series The X @-@ Files . " Sanguinarium " was written by newcomers Vivian and Valerie Mayhew and directed by Kim Manners , and is a " Monster @-@ of @-@ the @-@ Week " story , a stand @-@ alone plot which is unconnected to the series ' wider mythology . It first aired in the United States on November 10 , 1996 on the Fox network , earning a Nielsen rating of 11 @.@ 1 and being seen by 19 @.@ 85 million viewers upon its initial broadcast . 
