Season 2 Episode 9 - Firewalker 

Mulder and Scully, reunited at last, head for an active volcan under a geological study and find a deadly life form that can survive in the searing heat of the crater and is killing the scientists to avoid being discovered.
mots-clés: x-files, scully, mulder, full episode, season 2, episode 9, firewalker, 2x09