
Sure, we love Mulder and Scully—as well as Skinner and even that pesky Cigarette Smoking Man. And while a good portion of The X-Files’ magic came from the interactions between its regular cast members, the sci-fi series’ prolific use of guest stars helped elevate its storytelling, particularly in its wonderful “monster-of-the-week” episodes. It’s very hard to narrow down a list of favorites, but we’ve picked 15 actors (and yes, this list skews heavily male... as does The X-Files’ overall list of guest stars, but that’s a tangent for another time) who helped make the spooky sci-fi series one of TV’s most enduring classics.