 The episode started as a spec script written by two fans of the series . It features several references to real life witchcraft sources . " Sanguinarium " received mixed reviews from critics ; negative criticism was given to the number of inconsistencies in the plot . The episode 's use of gore also drew a mixed reaction ; some critics felt that the gore helped , while others felt that " Sanguinarium " relied too heavily on it to cover up weaknesses in its storyline . 
