(The mother all spoiler alerts: Please do not read ahead unless you’ve seen the “Westworld” Season 2 finale, “The Passenger,” which aired Sunday.)

The second season of “Westworld” took a cue from the Marvel Cinematic Universe’s handbook on Sunday, capping an insane finale, titled “The Passenger,” with an equally insane post-credits scene. In the short clip, we see the Man in Black (Ed Harris) aka William, stumble out of an elevator into an abandoned room that the hit sci-fi series has never entered before. He comes across his daughter, Emily (Katja Herbers), who, uh, he actually killed in the penultimate episode. The Man in Black is understandably confused, and so was TheWrap. So we asked the show’s co-creator Lisa Joy to explain it to us.

Here is what she said:

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TheWrap: We saw at the end of the actual episode, before the end credits scene that blew my mind, that William survived. He was one of the ones on the beach, in the tent in that particular situation and timeline. But then we get to the end credits: OK, he’s clearly a Host but I don’t know if that’s one version of him or another and then we see [his daughter] Emily there, can you give anything to explain that and at what point and in what timeline that might be happening?

Joy: Absolutely [laughs]. So you totally nailed what the story is, by the way, and then we threw in that last bit just to tease some other s–t that’s gonna happen, before you drown in it. So you totally got it, you totally got it. And that last bit, the reason we put it after the credits was because we wanted to be like, “No, you have it. You have the story and the timelines. This is some s-t that we’re going to do next” is what that other thing was.

But it recontextualizes itself when you realize that the entire season we’ve been going, we’ve been putting cards up in terms of our timelines. There’s been two major timelines. And it’s just the traditional story structure of a noir, right? Investigators come to town and they have basically a witness in Bernard who can’t remember what the f-k happened at the scene of the crime. And then you stumble back to the scene of the crime, which was this war that was happening.

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And the Man in Black is a part of that war. They are all moving towards the “Valley Beyond.” And when he gets right to outside the facility [the Forge] and after killing his daughter — who, you know, he doesn’t know if it’s his daughter or not — he’s still confused and like, honestly, psychologically spun out by his own sins, his own constant transgressions and living in this virtual reality. He himself begins to grow unsure of what is real and what is not.

And this leads to, you know, “these violent delights, have violent ends.” And he, in his confused and tortured mind, kills his own daughter, for real, and then proceeds to start hacking into his own skin because he doesn’t understand anymore what’s real and what’s not. And it’s grating him and haunting him. It’s in some ways a full reversal of what was happening to Dolores. He’s in a prison of his own sins and that prison is now his own damn mind.

Of course in that final showdown with Dolores, she rigs his gun and he basically blows off his own arm. Now, what we tried to do there is establish this context: he collapses on the ground, [Dolores and Bernard] go down, Dolores and Bernard have all the events that unfold down there. After Bernard kills Dolores, he goes to the elevator and you’re like, “Wait, the Man in Black! I think he’s gotten up and he’s coming down this elevator and they’re gonna meet! They’re gonna meet!”

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And then it’s totally weird because no one is in that elevator. And that’s our only little clue that something is not what we thought. That there is something else happening here. And that’s what we pay off later.

‘Cause in reality, a man got his arm shot off. He’s just lying on the ground somewhere. And later on, when Hale, or Halores is leaving the park, you see him on a cot. He’s injured, but he’s alive, and he’s real, and he’s going out into the real world — along with a handbag of pearls and Halores.

But then when you see that post-credit vignette, it’s really just a tease of what’s to come. We kind of rounded out that story. And you’re totally right about the end and this is a tease as to what’s to come, because we see that one tiny bit where we thought he might be coming down an elevator. We see that pay off and we see again Katja Herbers [Emily] who he thinks, “Are you my daughter? What the f–k is this?”

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But he’s in a very different timeline. The whole place looks destroyed, and then she explains that all of that stuff happened long ago. That was real. But now something has happened and the Man is now the subject — or some iteration of the Man is now the subject — of testing. The roles have become completely reversed.

And we get the feeling that, in the far-flung future, the Man has been somehow reconjured and brought into this world and he’s being tested the same way the humans used to test the Hosts. And that is a storyline that one day we’ll see more of.

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TheWrap: So because we do know that Emily died in the current timeline we’re in, is it fair to assume whoever is down there with this iteration of the Man in Black is similar to Dolores training Bernard? That has to be a Host or some other something if this is in the future and Emily died. Yes?

Oh yes, the Katja Herbers in the future talking to the Man in Black is now a Host version of Katja Herbers.

You can read our full interview with Joy about the Season 2 finale here.