Mulder: There's been a mistake here. Another agent's been attached to the case.
Krycek: That would be me. I'm Krycek. Alex Krycek.
Krycek: Reassigning them to other areas seems to have only strengthened their determination. Scully's a problem. A much larger problem than you described.
CSM: Every problem has a solution.
Mulder: Who are you?
X: Who I am is irrelevant.
Mulder: Why are you trying to help me?
X: You think I want to be here, Agent Mulder? I don't want to be here.
Mulder: All right, what do you want to know?
Krycek: What's the truth? There are things you're not telling me that I need to know.
Mulder: It's just that my ideas usually aren't very popular.
Krycek: I told you, I want to believe. But I need a place to start.
Scully: Sounds like your new partner's working out.
Mulder: He's all right. He could use a little more seasoning and some wardrobe advice. But he's a lot more open to extreme possibilities than. . .
Scully: Than I was?
Mulder: . . .than I assumed he would be.
Scully: Must be nice not having someone question your every move, poking holes in all your theories.
Mulder: Oh yeah, it's---it's great. I'm surprised I put up with you so long.
Mulder: So how do I contact you?
X: You can't
Mulder: I may still need more.
X: You still don't get it, do you? Closing the X-Files, separating you and Scully was only the beginning. The truth is still out there, but it's more dangerous. The man we both knew paid for that information with his life, a sacrifice I'm not willing to make.
Mulder: What is this?
X: Data from a top secret military project. Borne of the idea that sleep was the soldiers' greatest enemy.
Mulder: Of course. Someone was conducting sleep deprivation experiments on Parris Island.
X: Not deprivation, eradication.
X: Why else? To build a better soldier. Sustained wakefulness dulls fear, heightens aggression. Science had just put a man on the moon. So they looked to science to win a losing war.
Mulder: And Willig and Cole were the lab rats.
X: Lab rats with the highest kill ratio in the marine corps. 4,000 plus confirmed kills for a thirteen man squad.
Mulder: What's this scar right here?
Krycek: According to his medical history, the only surgery he ever had was an appendectomy.
Mulder: Well, unless they got to his appendix through his neck...
Krycek: Hey, I don't appreciate being ditched like someone's bad date
Mulder: I'm sorry if I hurt your feelings.
Krycek: Where do you get off copping this attitude? You don't even know the first thing about me.
Krycek: You know, back at the academy, some of the guys used to make fun of you.
Mulder: Oh stop it, or you'll hurt my feelings.
Nurse: This patient's night terrors prevent him from cycling out REM sleep into the more restful slow wave sleep. It's still experimental, but what we're trying to do is modify his brain wave patterns externally.
Mulder: How do you do that?
Nurse: Electrical stimulation of the occipital lobe creates simply visual and auditory hallucinations.
Mulder: So it's actually possibly to alter somebody's dreams?
Nurse: In theory, yes.
Mulder: Listen, I appreciate the show and tell, and I don't want you to take this personally, but I work alone.
Mitch Kosterman reprises his role of Detective Horton from 'Genderbender'.
At the end of the episode, Tony Todd's character Cole contemplates suicide by jumping onto a rusty, sharp pole from 40 feet. This is exactly the same way Tony Todd's character dies in the movie The Rock.
Writer/Producer Howard Gordon recommended Nicholas Lea for the part of Alex Krycek after seeing him perform in Season 1's "Genderbender."
The close ups of Mulder that were used during the scene where he first meets X were filmed with Natalia Nogulich, the actress originally cast as X when the character was going to be a woman. The shots of Steven Williams were added later. During some of the close ups of Mulder you can easily see the actress's hair shadow for a split second.
The name of "Krycek" comes from the Russian and Czech word "Krysa" meaning "Rat." This may be one of the reasons behind Nicholas Lea's affectionate nickname "Ratboy."
This episode features X's first appearance in person. In "The Host," X only appeared on the phone.
Character Name: Saul Grissom
Saul Grissom has the same last name as American astronaut Virgil Ivan "Gus" Grissom (1926-1967). Saul Grissom dies after being trapped in his apartment during an apparent fire. Gus Grissom and two other astronauts (Ed White and Roger Chaffee) died after being trapped in the Apollo 1 spacecraft during the 1967 launchpad fire.
Character Name: George Hale
When Scully's class is interrupted by the news that there is a phone call for her, the caller's name (it's actually Mulder) is given as Dr. George Hale. George Ellery Hale, Sc.D., Ph.D., LL.D. is, apparently, one of Mulder's heroes. In Little Green Men, Mulder tells Scully that Hale believed that his best ideas were whispered into his ears by elves, and that his (Mulder's) own life had been a struggle to hear, believe and verify what his own elves were trying to tell him. Hale was one of the most influential astronomers of all time. He won numerous scientific awards, founded two observatories and mentored Edwin Hubble, discoverer of the expanding universe phenomenon and namesake of the space telescope.