Spoiler alert! Do not read this piece unless you've watched the January 31st episode of X-Files.

After nearly 16 years, Scully (Gillian Anderson) and Mulder (David Duchovny) finally reunited with William (Miles Robbins), who is now known as Jackson Van De Kamp... albeit with a very X-Files twist.

The duo wound up back in their son's orbit thanks to an open X-file and Scully's mysterious vision, but things quickly turned tragic when it appeared he had died. However, it turned out that William's powers were greater than anyone anticipated: He was able to project images to other people to manipulate their perception of what was going on, thus tricking everyone into thinking he was dead.

Scully poured her heart out to his "dead" body, and Mulder confirmed that the young man was biologically her son. (They only checked his DNA against Scully, however, so the question about how truthful CSM was in the closing moments of the premiere is still up in the air.)

William caused mayhem at the hospital and managed to escape. However, he interacted with Scully at a gas station—while disguised—and told her, "I wish I could know you better." Scully was a bit confused by her interaction with the relative stranger... until Mulder pointed out he used a Malcolm X quote—an idol William frequently quotes. They check the gas station's surveillance tape and discover, yep, Scully was talking to William.

We spoke with writer-director James Wong about the inspiration for "Ghouli," filming the emotional hour, and what's ahead.

What was the genesis for the story? Did you first come to the Ghouli element and work William in, or was it the other way around?

I started with the whole sleep paralysis thing, because it happened to me in Mexico as I was shooting a movie. I experienced this crazy thing in a hotel: I felt a presence in the room, I couldn’t move. I was being chased or chased after this entity and then was in bed again. That was the genesis. It really affected me. So that’s how I started with it.

And it was the fifth episode, so we wanted to have a touchstone to the mythology of it all. [Executive producers] Chris [Carter], Glen [Morgan], Darin [Morgan] and I all talked about the idea of William. But I also loved the monster episodes. [Laughs] So it was how can we meld those two ideas that I love into something that is connected to William. And then you go, wait a second, William has special powers. So all of those ideas thread into each other and became this episode. I love hinting at one thing and the reality is different.

In the original run, William’s powers were hinted at, but there was also the thought that Spender injecting him with magnetite would neutralize them. What parameters did you have for what we’d see him showcase in this episode?

The parameters I had were based off of what happens in the teaser. I wanted to have a monster without a real monster. So I knew that I wanted the girls to attack what they thought was the monster. But at the end, you see there isn’t this external threat. In thinking about that, the teaser, it helped me gauge what sort of powers William would have in order to achieve that. It helped me think, if he can get in your head, what happens? You see it clearly, as if it was there. My thinking was the only way you can combat it is if there is an objective view of it, that can reveal the truth. Such as a surveillance camera, like the one at the gas station that revealed his interaction with Scully. That was the idea that helped me understand what his powers were and how they would play into this.

How did you go about casting Miles Robbins for the William/Jackson role?

It was interesting, because Chris and I didn’t talk about how important Jackson/William’s character could be to the show and its impact on the rest of the season. When I cast that, I cast Miles just for this episode. And it was really to the credit of Miles—he’s so great. He has a quality that really reminds me of how David is. And he has this heartthrob appeal to him without seeming like a CW character.

I found him on tape from New York—and it was through the process of shooting the episode. Chris was like, we have an idea for how the season could end, and Miles was so great that it impacted how we wrap up toward the end of the season.

One of the most moving scenes of the episode is Scully speaking to what she thinks is William’s corpse. What were the emotional tones you wanted to hit? And what was it like as Gillian filmed it?

Writing it was… I don’t want to say it was simple, but it was something I was thinking about for a long time as a parent and as a parent of an adopted child. I had all of these things I was thinking about anyway. [Laughs] So that came quickly.

I prepared for Gillian’s scene by basically getting a bunch of cameras together. We had more cameras than we normally have in the scene and just stacked them up. Gillian is a very instinctual actor, and she knows what she’s going to do. I just wanted—without having to do it over and over again—to get all the angles at the same time, basically. I talked to Gillian, and she was like, “Let’s do the meat of the scene—which is all the emotional stuff—right away, and we’ll do it first. And the prelude to that moment, we’ll shoot after.” So our plan was to stack up the cameras and Gillian came on and she was ready. We did it in I think three takes. She was super prepared, she knew what she wanted to do, and did it.

So much of the episode is Scully’s roller coaster of near-misses and grief. His biological paternity may be in question, but William is still a young man that Mulder considers to be his son. How did you go about demonstrating Mulder’s grief in the episode?

Well, I really do believe that, in the case of William, Scully’s character took the brunt of the emotional journey and baggage. She was the one who had to do everything by herself, really, and she made decisions for him by herself.

To me, Mulder’s emotional journey is really through Scully. I felt like he was trying to support her; he could only connect to it through her. And that’s how I approached it. The moment it felt like Mulder was able to express his grief was when he and Skinner were talking on the boat. The moment I really love is Skinner is warning him to stay away, and Mulder is like, 'Thanks for the warning, but you’re too late.' The moment he turns around, we saw him not saying that to Skinner, but saying that to himself. The whole thing was too late for him. So that’s the moment I liked.

By the end of the episode, Mulder and Scully know that William reached out at the gas station and it seems like he’s going to be OK. Was it important for you to leave them with bit of hope?

I think it’s interesting to think about what William thought about Mulder and Scully. I wanted to show that William didn’t have a horrible upbringing with his adoptive parents. I really wanted to express that—that part of it was right, and Scully made a good decision. And then for him, he’s like, who is this person who has this emotional [reaction]—because he heard [Scully’s speech] as he was lying there in the morgue. There’s a little bit of a standoff, because he’s like, how should I feel about my biological parents? He’s testing the water. And then at the end, I think that’s the result, when he tells Scully, 'I think you’re a nice person and I wish I could know you.' To me, it was very poignant and heartbreaking. And at least they find out he’s alive.

You’re also directing another episode later this season about the quest for youth. What can you preview about that?

Well, it’s a totally different feel. [Laughs] I’m really happy with it. I’ve been working on a show called American Horror Story, and to me, this is the closest to American Horror Story that The X-Files has ever [been]. It’s pretty creepy and weird. And there is some kind of icky thing. But at the same time, there is a very important and emotional thing that happens with Mulder and Scully. I’m really happy with it. I’m excited for people to see it.

That sounds great. Is there anything else you want to make sure people know about “Ghouli”?

The one thing I do want people to know is there is actually a Ghouli.net. [Laughs] It’s a website we launched the other day, so there’s the opportunity for fans to write their own stories there, to submit their own sightings, and see stories we have on the website. It should be good and really fun. Hopefully, people will connect to it and make it come to life.