[WARNING: The following contains spoilers from Sunday's Once Upon a Time episode. You've been warned, dearie!]

Maleficent the malevolent! Maleficent... the mother?!

On Sunday's Once Upon a Time, viewers learned two huge secrets: Maleficent (Kristin Bauer van Straten) was once a would-be mom, and that somehow, Snow White and Prince Charming (Ginnifer Goodwin, Josh Dallas) were responsible for the loss of that dragon-child way back when they were all in the Enchanted Forest. We have so many questions, but first and foremost: How is a baby Maleficent made? "You will learn how it's made and how she gets it," series co-creator Adam Horowitz tells TVGuide.com. "What we're going to see is the critical juncture of how the baby is born and what comes a bit after it's born. We're going to obviously explore how she lost her child. And at that end of that episode, I think you can see on her face that it was a very painful experience."

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For Bauer van Straten, this new dimension of the classic Disney villain was a welcome change. "It was really enjoyable at the beginning to think she's just 100 percent reptile and doesn't have the DNA to feel remorse for her actions, 100 percent selfish in her goals and desires," the actress says. "I imagined what it was like to be pretty much all the billionaires on earth. Then it thrills me when I actually can put some sort of Achilles heel in there and that it becomes part of that pure pain, that she imagines it will feel good and make her feel happy to make that pain she feels inside to make someone else feel."

Maleficent certainly has pain on her mind when she confronts Snow in her Storybrooke guise as Mary Margaret. It's not clear whether or not her kids Emma (Jennifer Morrison) and baby Neal will become targets though. "It's so much fun to play somebody who has time on her side in that she's immortal," Bauer van Straten says. "She doesn't have to rush for her revenge. Killing someone in this realm, this isn't a John Wayne sort of revenge. This is like, 'I will take my time and I will watch how things develop and I will figure out how to keep the pain happening as long as possible.' So we have the whole season for Maleficent to try to work that out. But of course there are other people who are going to try to not have that happen, so this is like Olympic chess."

The actress, a die-hard animal advocate, took inspiration from a particular kind of snake to play Maleficent. "I was in Africa last year, and the black mamba is a terribly frightening, fascinating snake that is territorial and will hunt you," she explains. "It's so fast; you can't get away and feels no remorse. I tried to have it inform my body movements and how I would transform into a dragon. I had to make up something physical and hopefully make it look really cool. So I used YouTube videos of reptiles for the inspiration."

Read on to see what the else the co-creators have to say about the episode:

How much will we explore Hook (Colin O'Donoghue) and Ursula's (Merrin Dungey) past?
Edward Kitsis:
We're getting a whole episode. Episode 15 will explain what he did to her. It was not sexual. It is, as he said, far worse. When you think about what would be worse than having your heart broken. I would say it was having your soul crushed. You're going to see the entire flashback of what happened. You're going to see the entire origin of Ursula.

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How does Ursula's dad fit into that? You cast Ernie Hudson as her dad.
Kitsis:
Similar to what we've done with Cora, Young Cora and Emma, Young Emma, we're going to meet Ursula at about 18 or 19. As we all know, Hook is about 385 years old. It's the guyliner.

What challenges are coming up for Emma now?
Kitsis:
For Emma right now, the two people she trusts the most in her life are lying to her, and she's suppressing that. So finding that out will be kind of a bummer. She's done a lot of growing over the three and a half seasons. And what happens when you find out that the person who is helping you grow might actually be as bad as the people you're trying to get away from?

David and Mary Margaret are now driven to lying and drinking. How bad is this secret?
Adam Horowitz
: In many ways, it's the worst thing that either one of them have ever done. We're going to explore what that was and how it shaped who they are now.

Is this whole secret arc going to somehow tie in with the fact that they share a heart that has a dark spot on it?
Horowitz
: The heart having a dark spot will absolutely be addressed, but it's not necessarily tied to the secret.

How does Mary Margaret's decision to open up to Regina (Lana Parrilla) about this secret change her guilt and shift that relationship?
Horowitz
: Snow was [once] asked to keep a secret and couldn't keep her mouth shut. Can Regina keep her mouth shut? I'd say Regina is probably a stronger and better secret-keeper than Snow White. But it does create a bond between the two of them, a bond that's gone back a really long time. She was her stepmother

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Why did you decide to pair Belle (Emilie de Ravin) and Will Scarlet (Michael Socha)?
Kitsis:
Any time you have your heart broken, you look for a way to smile again. .. They both fell in love with villains. They both hoped that these villains would be redeemed. He fell in with the Red Queen, and she changed, and he saw the woman beneath the monster, and that's the same with Belle. So they have a lot in common. What we loved about Belle in the winter finale was she was kind of like, "It's enough. It's enough lying." At some point you have to stop giving people the benefit of a doubt. You have to say, "Change or f--- off." We love that strength from Belle, and we love her moving on. It's like if you got married at 21 and now you're 32, you kind of might think, "I want to live again."
Horowitz:
Belle has to be strong. One of the things that happened in that relationship with Rumple is as his lies grew and as his betrayals grew, the audience was seeing that Belle was unaware of any of this. We really wanted to build in the first half of the season her discovery and letting her act out of strength. And now, if they are to have any chance of being together, she has to be a strong person. What he has to do is ultimately probably going to prove difficult.

Will Will Scarlet be a target for Rumplestiltskin/Mr. Gold (Robert Carlyle)? How jealous is Rumple?
Horowitz:
He's not happy.
Kitsis:
Listen, the last person who took his woman was Hook, and he took his hand off and killed his wife, so I'd be worried.

How much more of Rumple will we see going forward?
Kitsis:
You have a man who's lost everything, literally as we saw now. Belle has moved on. He is going to do his Rumple-est to get it all back. You're going to see full Rumple.
Horowitz:
After what happens at the end of that last episode, he doesn't disappear. That activates him in a way and starts him on a new quest that he's really energized about.
Kitsis:
The Queens of Darkness believe they're working with Rumple, but we all realize that you work for Rumple.

Apart from his new relationship with Belle, will we learn more about Will? Will there be flashbacks?
Horowitz:
We are going to see Will in a flashback with Robin Hood (Sean Maguire). And we are going to absolutely get a little more information about him through that.

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