X
Out of all the contacts, X is the least trustable. It is my belief that X was just after the weapon that is capable of killing the aliens. In "talithia cumi" mulder and X got into one hell of a battle because mulder wouldn't give X the weapon. almost killing each other. but through the times X has given the agents alot of valuable information. It also seems that X follows mulder where ever he goes. all mulder needs to do to summon X is put tape in the shape of an x and he will magically appear.
X got tricked to go to mulder's appt. where a killer was waiting for him. shot and bleeding X crawled to mulder's door and wrote SRSG in blood. it was a message that would lead him to his next contact.
