Mackenzie Phillips, left, and Henny Russell.

Spoilers for Orange Is the New Black season six ahead.

The Orange Is the New Black inmates haven’t had a villain in their midst since Vee antagonized the penitentiary way back in season two. While last season brought in an enemy from management in the form of a corrupt prison guard, season six doubles the evil with the introduction of two new inmates who’ve quietly been there all along: Barb (Mackenzie Phillips) and Carol (Henny Russell) Denning, known as the Little Debbie Killers, have been serving life sentences on dueling Litchfield maximum-security blocks for intentionally drowning their youngest sister in the ’80s when they were teenagers.

Barb and Carol are as chilling behind bars as they were on the outside, using their continued sibling rivalry over a misunderstanding — which only escalated after a young Freida double crossed them to get out of max — to fuel a prison-wide gang war that ultimately turns deadly for both of them. Vulture spoke with Phillips and Russell about the OITNB scene you didn’t see, what they think of Barb and Carol fandom, and those chilling flashbacks. Phillips also opened up returning to acting to play an addict after years of her own recovery.

How did you both get cast? Mackenzie, I’m wondering if Norman Lear maybe put in a good word at Netflix?

Phillips: That was my first thought, too, because of my recurring role on One Day at a Time, so I asked. But they had nothing to do with it. I was talking to one of the EPs and she said she found my name on a list and just went, “Yes! I love Mackenzie Phillips! Let’s get her!”

Russell: I actually auditioned with a young Barbara scene in the library. I didn’t know that at the time, but there wasn’t enough dialogue in my first episode to have a long enough scene. I really thought there was no way I would book it. Even talking to my husband, I thought I was so not right for this and he said, “I don’t know, Hen, you can be pretty scary.” But I was a huge fan of Orange before Carol Denning ever existed, so it was thrilling and also a little terrifying to jump in. I’m working with these iconic actresses — Mackenzie and Kate Mulgrew — and I’m supposed to be top dog. I’m dominating them. It was daunting.

Mackenzie, were you concerned that playing an addict might dredge up some old personal demons?

Phillips: I wasn’t worried about it. I had shifted gears in the last five or six years — I went back to school to become a counselor and I’ve been working in the behavioral health world. I stopped acting. I did One Day at a Time because it’s One Day at a Time and it’s Norman and it’s Rita Moreno. But I had told my agent not to submit me for roles because I love my counseling work. But then she called and said, “I know you said not to, but OITNB called.” What?! Are you kidding me?! All I knew about the role was I was a drug kingpin, a lifer, unpredictable, erratic, and violent. Who wouldn’t wanna do that? It’s such the antithesis of me. You’d be crazy to say no.

You work with addicts in recovery, but to revert back to the mind-set of an addict after decades of being in your own recovery, how’d you manage it?

Phillips: It was a challenge for sure. The bleak setting really helped. You feel like you’re in prison when you’re on set — there’s no color, it’s very gray and dusty. I was able to put myself in that place of someone who knows they’re never getting out, so why even try to better yourself? Almost her entire adult life has been spent in prison. I know it doesn’t sound like fun, but it was fun for me to be able to access that place that was hopeless. Because it isn’t for me anymore, but I still know what it feels like.

I read that you really committed to making Barb’s drug abuse seem authentic, to the point that you gave direction on how snorting drugs should actually look. And then you had to fake tripping out on bath salts.

Phillips: That was wild because she’s seeing something that isn’t there. It was almost mathematical because I had to be very precise with where I would look when she’s seeing flies and a person that’s a frog. We filmed for 16 hours that day. Natasha [Lyonne] and I were like, “Oh God, if we have to eat anymore pudding…” But the next day, because I’d been in restraints and thrashing around, my body really hurt. I felt like I got beat up. But you just have to commit. You can’t care how you look.

I didn’t have to practice with the straw and the baggie — I’ve done that a million times — but I had to remember that it wasn’t me. I walked away from my scenes thinking how dark it was to live that way. I felt bad for Barb that that was the highlight of her day. When I told people at the recovery center that I snorted fake drugs that day, they were like “Oh my God, weren’t you so triggered?” No, I felt so free. It wasn’t real. My recovery was protected.

If you had to film a scene like that when you were using, do you think it would have been more difficult to get through?

Phillips: I probably would’ve tried to put real drugs in the baggie. [Laughs.] I have a great sense of humor about it because I don’t live that way anymore. I can understand that my past is my past.

Present-day Carol and Barb don’t have as many scenes together, but every time it’s just you two in the same frame, it’s electric. Tell me about filming together.

Russell: We filmed this scene that never made it in, when we’re first thrown together in Ad Seg. We spent a lot of time with the cameras rolling, no dialogue. Mackenzie and I just had an entire silent conversation from across the room from each other. I found myself running the gamut from being furious, to realizing that I missed her, to being disgusted, to being sad and almost having a tear in my eye, to wanting to rip her face off. All in this silence. It bonded Mackenzie and I because it was all coming from a deep place within us.

Not to diagnose these women, but did you find one sister to be more disturbed than the other? I think the drowning scene speaks a lot to their sadistic personalities: Barb has this moment where she doesn’t totally resent Debbie, then still kills her. Meanwhile, Carol never exhibited any basic humanity. The murder was her plan.

Russell: I think they clearly are both sociopaths. To me, it was almost more disturbing that Barb did have that moment with Debbie because she appreciated her and then went ahead with the plan anyway. But Carol doesn’t seem to have any sort of conscience. They both use people to their own advantage and lack empathy for anyone but themselves.

Phillips: Something to think about when Barb gets sober — what you do with your recovery is entirely up to you. Barb decides to use it to bring people down instead of lift them up. Barb just stopped using, but she didn’t work on her issues. She just goes, “He he he, who can I kill?” It’s that justified anger and revenge that she can’t let go of, which is what you do in recovery.

Young Carol and Young Barb, played by Ashley Jordyn and Lauren Kelston, have quite the fan following. People want a spinoff focused on Litchfield in the ’80s, when Barb, Carol, and Frieda were new arrivals.

Russell: I know! What’s funny is Ashley and I have become friends. We met on the set and bonded and we’ve hung out since we’ve wrapped. The casting is so spot-on and they play so well off each other. My first day shooting, Ashley had shot one of her scenes beforehand and I was allowed to watch from the dressing room. So I got to watch my younger self to see what I was like, which was a wonderful advantage.

For example, the lollipop. A lot of smokers become orally fixated, so the very first scene I shot, I had a toothpick in my mouth. The more I thought about it, I thought, “What if she has this oral fixation with candy even as an adult?” I loved the idea of her telling Badison, “Don’t do that baby voice” with a lollipop in her hand. It’s hilarious. I went out and bought a bag of Charms Blow Pops, but then I found out that you can’t have gum in prison because you can jam locks with it. So then I bought a bag of Tootsie pops and told the writers about my idea. They loved it! From then on, the props person and I would decide if she had a lollipop that day or not. In one of the flashbacks, we had Ashley have a lollipop, too. I loved the idea of this psychopathic killer with candy.

Phillips: Oh my God, it’s amazing. People are obsessed. I’ve seen people saying there needs to be a prequel spinoff. I love that they got someone with big teeth and the same kind of small face. You could see that years in prison could turn that beautiful actress into what Barb becomes.

young!carol denning was a raging lesbian and that’s the tea pic.twitter.com/uT53e1L5oL — ‏ً (@caitylvtz) July 31, 2018

Have you seen the Carol as gay icon memes? There’s even this fan theory she might’ve been in love with Frieda, and that’s the real root of her need for revenge.

Russell: I’ve seen the Instagrams! It’s awesome. I’m happy for Carol.

It’s also amusing that Netflix seems to be building its own cinematic universe of redheaded characters from the ‘80s named Barb.

Phillips: I’ve seen some of that! I’ve been knee-deep in social media and it’s unbelievable the amount of comments and memes Barb and Carol keep generating.

Mackenzie, do you think you’ll keep dipping your toes into acting while doing your work at the treatment center?

Phillips: I think I will. I’m not as tied to the location as I used to be when I carried my own caseload of clients. I work more as a director in upper management now and I can work remotely. It would be nice if more acting opportunities start materializing. I’m almost 60 years old and I’m having the best time of my life. I was really, really adamant for awhile about keeping acting as a thing of the past, but it found me.

This interview has been edited and condensed from separate conversations with Phillips and Russell.