All original characters, dialog and situations used from Star vs The Forces of Evil are © 2015-2019 The Walt Disney Company.

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All original characters, dialog and situations used from the fanfics are © 2015-present by their respective authors.

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This is a work of fiction portraying alternate universes; all similarities to beings living, dead, or undead are entirely convergent.

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Possible spoilers between the ⭐⭐and 🌟🌟.


II

The Saturday peace and quiet of the Diaz living room gave way to the sound and light of an opening space-time portal. Star and Marco jumped out of the portal together, hand in hand. After Marco closed the portal and holstered the wond at his waist, Star said, "I knew you could do it!" She kissed him on the cheek.

⭐⭐ The two looked around the room, the familiar paintings, pictures, furniture, and knick-knacks making them feel at home. When their gaze reached the sofa, they discovered they were not alone. Looking over the top of the morning newspaper was ... Toffee. "Hello, princess," he said.

"Toffee!" Star exclaimed. "What have you done with the Diazes?"

"Not that it's any of your business, young lady," Toffee answered, "but their business was elsewhere this morning." Toffee turned his yellow eyes to Marco. "What is the meaning of this, young man? Why are you ..." Toffee stopped, realizing Marco was taller, more heavily built, and clearly older than the Marco he knew.

"Won't talk, eh?" Star fired a laser-like beam of magic at Toffee, taking his left arm off at the shoulder. "Cover me, Marco!" As Marco pulled the wond from its holster, raising it menacingly toward Toffee, Star stalked forward, hands aglow with magic.

To the surprise of the two attacking teens, a familiar-sounding voice cried out, "Stardust Daisy Devastation!" A yellow energy beam containing daisies slammed into Star, knocking her into the far wall. The voice said, "Marco? What are you doing ... and is that a wand?"

As Star picked herself up off the floor, she noticed a look of shock, if not horror, on Marco's face. She looked in the direction he was staring, gasping at the sight.

Holding her wand threateningly at the teens stood the AU's Star, but a Star they'd seen only once before. The Star in front of them appeared to be half Mewman and half Monster. Her calf-length hair was bluish-silver, her skin was gray like wet concrete, and her Magic-Pips were a dark rose color. She had a long reptilian tail, claws on her hands, sharp reptilian teeth, and her eyes were yellow and cat-like. Star and Marco recognized it as the form Star took before she turned entirely into a Mewmonster.

Seeing that Star had risen, MonStar demanded, "Sophia Rose, what is the meaning of this attack on my father?"

"Your father!" Star exclaimed. In shock, Star and Marco looked at Toffee, who was rising shakily to his feet. He winced and groaned as he regrew his arm.

MonStar kept her wand at the ready, shouting, angrily, "I asked you a question, Sophia!"

Star responded, "My name isn't Sophia. I'm Star Butterfly, a magical princess from an alternate universe, and this is my boyfriend, Sir Marco Diaz."

Toffee looked between the older pair and his daughter twice, then signaled to MonStar to lower her wand. "I think we should talk."

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The four sat at the Diaz kitchen table, where Toffee and MonStar, her eyes having returned to their normal green, looked at Star and Marco with suspicion. Star kept looking from the Monster girl to her father, then back again, wash, rinse, repeat, with a look of horror on her face.

"That's not very princess-like, young lady," Toffee admonished Star.

"Wait, wait, just one second," a voice said. The AU's Janna walked into the kitchen, situated herself in a chair, then began eating from a large bucket of popcorn. "Continue, please," she said.

"Janna?" MonStar asked, "what are ... you know what, never mind."

Despite Toffee's criticism, Star could not stop staring. Finally, she asked, "If Toffee is your father, who is your mother?"

"Queen Moon Butterfly of Mewni," MonStar answered.

Star's eyes grew wide. "My mother made it with Toffee?" she shouted. Star and Marco both shuddered involuntarily.

Out of sheer habit, developed in response to herself and her father frequently being addressed in a disrespectful manner, MonStar said, "You will refer to my father as 'his majesty.'"

Janna turned toward the wall with the Fantastic Four wall clock, the wall the AU's Diazes referred to as the Fantastic Fourth Wall. She said, to no one in particular, "How will this conflict be resolved? This should be good..." Janna turned back to the conversation.

Star and Marco looked at Janna in confusion, then back to MonStar and Toffee. Both gazed back at the teens, behaving as if that was a normal thing for Janna to do.

Once again, Marco thought, Janna is weird and creepy.

Deciding to ignore the strange occurrence, Star continued, "His majesty? As in, 'King of the Monsters?'"

"I am that," Toffee answered, "and also Sebastian Augustine Bartholomew von Lizard Butterfly, King of Mewni."

"And what do you mean by 'my mother' when speaking of my mother?" MonStar asked.

"We're you and your Marco from a different timeline."

"Oh ... I actually understand that," MonStar replied. "Marco introduced me to Earth stories and movies based on the concept. I was intrigued by the idea, but the physics of it, especially around the potential impact on universal entropy and the law of conservation of mass and energy, made me doubt such a thing actually existed. I thought that even if the concept was sound, travel between differing timelines would be impossible."

"Wow," Marco said, impressed, "you're really smart."

It was hard to tell with her gray skin, but MonStar blushed at Marco's praise. "I don't know about that, but I do study."

"See, Star, Skullnick was right, all you had to do was st...OW!" Marco rubbed his shin where Star had kicked him.

"I take it from your reaction that in your universe Monsters and Mewmans do not fraternize?" Toffee asked.

"They didn't, for the most part," Marco answered. "Mewmins and Monsters have fought many wars over the centuries so there's not a lot of trust there. But Star has been working hard to change all that, and attitudes are changing, especially after recent ... difficulties." Marco reached over and squeezed Star's hand, saying, "I'm very proud of her for it."

"Then why do you two look at papa with so much hate in your eyes?"

Star and Marco looked sidelong at each other.

Observing the glance, Toffee said, "I surmise that you two have a history with your universe's Toffee, and it is not a positive one."

Star sucked in a breath, then let it out slowly, shuddering. "The only thing my mother made with our Toffee was war. He assassinated my grandmother when she was about to sign a peace treaty with the Monster king." MonStar gave a slight gasp, thinking of her beloved grandmother, whom she had talked to just the previous day. The gasp drew Star's attention. Looking MonStar directly in the eyes, Star continued, "Our Toffee was evil, and I had to commit suicide to defeat him."

"Suicide?"

"Yes. I used the Whispering Spell. Do you have the Whispering Spell here?"

"Yes." MonStar held up her wand. It looked very different from Star's various wonds, yet still kindled a feeling of familiarity, especially when it came to its half-crystal. "That's why the crystal is cleaved; I used the Whispering Spell to save Marco when he was kidnapped by Lord Mildrew, who threatened to kill Marco unless I destroyed the wand."

"Lord Mil ... never mind. I first used the Whispering Spell to save Marco when he was kidnapped by Toffee, who threatened to kill Marco unless I destroyed the wond. The wond came back, but with half a crystal, just like yours. I used it a second time when Toffee staged a coup, acting through Ludo and a wond made from the other half of the crystal. I effectively killed myself by using the spell again to destroy that wond, too."

Out of the corner of her eye, Star saw Marco look down and away. She reached over and took his hand.

"My spirit, katra, whatever, was transported to the realm of magic. Long story short, I recreated my body, then blasted Toffee into goo, making him very, very, dead." Star glanced at Toffee, who regarded her impassively.

MonStar cocked her head, removed her hairband, then said, "Mewmando näyttää ja kuulostaa aivan kuten suomen kieli." Star looked at her in confusion.

MonStar replaced her hairband. "So, you don't speak Mewmando? That makes it harder to believe you."

"I'm speaking Mewmindo right now; what you said isn't Mewmindo."

"It most certainly is Mewmando. You're speaking Earth English."

"Ah. I guess that's another difference. In our universe, Mewmindo looks and sounds just like the English language."

MonStar appraised Star, looking her up and down. "If you're me, how is it," she asked, "that I'm half reptile, while you're older than me and entirely mammal, yet I have bigger mewbs?"

"Star!" Toffee admonished his daughter. "That's not very princess-like, young lady."

Marco smiled at Star, stating, "Aw, I like Star's teeny tiny little ..."

"Shut it, Marco!" Star interrupted loudly.

MonStar looked back and forth between the two teens several times, smiled toothily, then said, "I believe you ... so, how do you two do it?" Star dropped Marco's hand, as the pair blushed.

Janna again turned to the wall, saying, "Well, now that's just lazy writing to keep the tension high."

MonStar chuckled, glancing at her father. Commenting on the blushing, she said, "See, papa, me and mama aren't the only ones who think dirty thoughts." Speaking to Star, she said, "I meant, how do you travel to other timelines?"

After a slight pause, wondering why Janna's strange behavior continued to be ignored, Star began, "Well ..."

"No," Toffee interrupted.

"What?" Star asked. "Why?"

"There are many multiversal theories. One of the most popular is that the different universes have always been separate, and any similarities are convergent. It's considered a side effect of the Big Bang, as Earth scientists call it. But there's another popular theory, that time is like a river, and any major event with multiple possible outcomes causes a branch of the river for each outcome; a so-called Nexus Event."

Toffee gestured at MonStar. "We subscribe to the latter theory, despite the issues that my shining MonStar noted. In this model, the same events could occur in multiple universes, but in different orders or at different times. Knowledge of a second universe's events by natives of a first could change the course of future events in the first universe; possibly with catastrophic results. I presume you've visited other, what I'll call for brevity, AUs?"

Star and Marco nodded.

"And did you use that knowledge to change events in your own AU?"

"Nope," Star answered.

"Subconsciously, perhaps?"

"Nope," Star repeated.

"That's fortuitous, but I just accidently impacted the flow of events in your AU by bringing your attention to something you had not realized before. As fascinating as this has been, I think we should stop this interaction, and you two should go home. I think I speak for my MonStar when I wish you better luck changing your Monster-Mewman relations than we have been having."

"Papa! You did it again!"

Toffee shook his head. "You see how easy it is? Fare thee well."

MonStar stood and curtsied. She said, in an amused tone, "It was an honor to meet me." She winked and blew a kiss at Marco, saying, "Love ya, Sir Boo."

Everybody jumped when, unexpectedly, a voice yelled, "What is going on here?" Moon and the Diazes, including Marco, stood in the entryway to the kitchen, wide eyed.

Toffee turned to his wife with a wry grin on his face, saying, "Surprise!"

Turning to the wall, Janna said, "Oooooh ... what do you think of this little cliffhanger, SN?"

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The quiet and darkness of Star's room gave way to the sound and light of an opening space-time portal. Star and Marco jumped out of the portal together, hand in hand. After Marco closed the portal, the two threw themselves onto the sofa, tired but happy.

"Wow, that was something, wasn't it?" Star asked.

"Yeah," Marco replied, "an actual Monster Star that wasn't the result of a transformation spell."

"No, dummy, I'm talking about mom ... I mean, Moon ... and all those scars and tribal tattoos."

"Ah."

"And then her and Toffee acting like a couple of horny teenagers toward each other and making out in front of us ... well, like your parents do." 🌟🌟

"So," Star began, as a calico cat with wings and a small gem in its forehead, carrying pen and notebook, appeared from a cloud of black smoke and pink glitter. "Wait, you're not Babystoat."

"Babystoat is my father," the flying cat answered. "I'm taking over his duties as your Alternate Universe chronicler." His voice was deep, but he sounded more like Darth Vader or Mufasa than Babystoat. "Jej is my name, and I'm so happy to be of service, milady."

Star began breathing hard, as her tongue lolled out of her mouth. She began to drool as she slowly reached for Jej.

"Star!" Marco yelped. "You're not a monster anymore, you can't keep eating cats!"

"What? Oh, right, um ... happy to have you join us Jej, but please don't ever call me 'milady' again. Anyhoo ..."

Star and Marco recounted their adventure, making sure to be detailed in their recollection of what they'd been told about the dangers of visiting AUs.

"Um, Star," Marco started carefully, "did you really mean what you said about not using knowledge from AUs?"

Sensing the account was over, Jej bowed, then disappeared in a puff of black smoke and pink glitter.

"Sure. You were there all those times. I haven't."

"Um ... I think you did."

"What?"

"You've been friends with Kelly for what, almost a decade?"

"Yeah, sounds about right."

"Then why did you suddenly become so frosty, if not hostile, toward Kelly where I was concerned?"

"When was that?"

Marco sighed. "You don't remember failing to mention that Kelly had been invited to take part in the presentation of the Petition of Friendship? And the way, before and after the meeting, you were so frostile toward Kelly?"

Star blushed, saying, "Yeah, I guess I do."

"Tom also told me that when you saw Kelly give me a congratulatory kiss for being knighted, you growled. You actually growled."

Star did not reply, blushing deeper.

"Star, that all started only days after we visited the AU where Marco and Kelly had that bizarre 'friends with benefits' thing going on."

"So?"

"So, you still hadn't accepted the fact that you were in love with me. Deeply, madly, over-the-moon, apocalyptically ..."

"Okay, don't over sell it."

Marco grinned. "Point is, you were subconsciously using what you learned in that AU, and it was damaging your friendship with Kelly."

"Okay, I get it. But counterpoint, what about Meteora? It didn't occur to me that she might be wanting the throne of Mewni like in those other AUs until she said so, but what if it had? What if it had occurred to either of us? Maybe we could have ended the whole ugly affair before it started." Star scowled. "If I hadn't been so damn wrapped up in our drama ..."

"We can ... should, maybe ... talk about our drama later. But for now, let me ask you this: what if we had acted on that knowledge and hunted down and captured Meteora, or killed her trying, for something she hadn't done yet? How would that have looked? Even if Eclipsa believed us, I can't see her responding well. She didn't believe Meteora was a lost cause until the very end. Remember, we've visited an AU where Eclipsa killed Moon, resulting in Star and Marco killing Eclipsa."

"Meaning what?"

"Meaning, acting on the knowledge from those AUs, we could have made things even worse. Just because that other Star survived to become Queen after fighting Eclipsa, doesn't mean you would in our universe, or that the fight wouldn't have devastated the kingdom, resulting in even more death and destruction than what actually happened."

"Oh."

"Also, we're not supposed to enter an AU where Star and Marco are, yet we did, again. In this case it was probably because Marco was not there and MonStar was only half Mewman. It never occurred to me that was a possibility, so when I cast the spell, I didn't control for that; the magic, through me, 'thought' Star wasn't there."

Star sighed, looking away from Marco.

"Stardust, I'm not being critical of you. Everything I've said is true of me, too. I didn't realize at the time your frostility towards Kelly was due to that one AU. And because I was wrapped up in our drama, same as you, I didn't think through the consequences of bringing up to you the relationships I was seeing between those other Stars and Marcos. If you don't remember, I even told you that seeing that one AU's Star and Marco about to have a kid influenced my decision to return permanently to Earth."

Star looked back at Marco, smiling. "Mess-up twins?"

"Mess-up twins."

They shared a quick kiss. "Look," Marco continued, "I really enjoy visiting AUs and don't want to stop. But we're playing with fire here, and I think we need to come up with some new 'rules of engagement' to minimize the risk, starting with not interacting with the beings of AUs the way we did today. Just because they allowed us to use the Mind Eraser spell on them, doesn't mean all, or even any, beings in other AUs will. We shouldn't interact with beings in AUs at all, until we can figure out how to do it in a way that there'd be no chance of damaging theirs or our universes. So next one, we stay way out of sight, okay?"

"Okay. Deal."

Marco grinned. "Guess I'm no longer entirely the 'Safe Kid' I was when you first met me, otherwise I wouldn't be visiting any more AUs." His grin faltered. "I hope I don't destroy any Mewnis because of it..."

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⭐⭐ Inspired by Star The Monster Princess by The Wandering Hippie (www dot fanfiction dot net /s/12794260). 🌟🌟


As always, stay amazing!


A/N:

Readers will recall that Mewmin and Mewman are both canonical spellings of those words, the former on-screen and the latter in the books. The same goes for wond and wand. I always prefer on-screen canon when sources disagree, and explain the existence of both by saying they're accepted alternate in-canon spellings, like gray and grey are in reality (or our alternate universe, depending on how invested you are in this story).

When trips to AUs are related "real time," I've decided to use the book spellings when narrating the AU. This is to further distinguish this story's universe from the alternate universe being visited, given there will now be two or more of the same beings in the tale at the same time. I think this works because it's highly likely that in the fanfics most AUs are based on, the book spellings of the words were used.

When reading, just remember that, regardless of spelling, each variation is pronounced the same.

This was something I came back and added after writing later chapters; it's not so easy to distinguish who is speaking when it's plain old Stars and Marcos and not a half-Monster girl and her Monster father. To establish the convention I deliberately made it in-your-face and over the top (e.g. Mewmindo and Mewmando) in this "fun" chapter so that it's just helpful background stuff when the deeply serious plot gets moving next chapter (oops, I impacted our AU just like Toffee warned).