Morty knows he shouldn't be screwing around with multidimensional shit. It's dangerous, it's impractical, it's blah blah blah. But it's a potential key to unlimited energy, how does nobody see that? He's built a dimensional siphon (it kind of looks like a cardboard box with a funnel and a TI-84 taped to it, but it damn well works), keyed in the dimensional coordinates to a random plane, and by God he's going to use it.
He flips the switch and waits for the energy bar to fill up.
It does! It fills up very rapidly. Then it explodes, along with the box. There's rather more smoke than there should be, and once the smoke clears someone is standing there.
"Oh dear," Morty says faintly.
"If you pick a room we can start getting you set up. If you really want to speed it up we can get Zip in here, she's a speedster, but she's... kind of a handful? So... room, whether or not to involve Zip, and letting me finally end my stunning Carmen Miranda impersonation."
"South American singer-dancer-actress from the 40s. Known for, ah, elaborate headdresses. Hers usually involved more fruit than this."
"I can fix the glitter," Ariel notes. "Duster spell's easy, I learned it in Intro to Mystic Concepts."
"I'm leaning towards the east-facing one, actually, I've noticed that I've changed time zones as well as dimensions."
"Well, it would be a very strange world if we were all alike." Ariel tosses the bedding etc in the middle of the room and begins flitting about setting things up.
"Oh yeah, because I totally had stuff to do this afternoon. It's a Tuesday, I can't even go beat people up in the combat sims 'cause they're only open weekends and during classes. I was gonna beg a video game off some programming Devisor or something and think unkind thoughts at Sally for abandoning me to boredom. Not that you're not ultra cool and all, but like... no great sacrifice, you know?"
"They're this big devisor computer system, you sit in a chair and hook up electrodes to your nethers and it projects you into a virtual reality where you can punch people. It's a flawless simulation of reality and there's a full sensory hookup and all, it's like beating the shit out of people for real except there's no pesky laws. Or getting the shit beaten out of you, that happens too. Not usually to me, but it's been known to occur. It is my favorite thing in this world, bar nothing. Sex has nothing on the sims."
"Well, there's access to my other favorite things too, this school is a few square miles of hormonal teenage mutants who look like Playperson centerfolds for bullshit magic reasons. And I am the most beautiful toad in all this pond, as you may have noted already." She twirls in midair, not that she wasn't already doing that on a fairly regular basis.
"Twins do not get that particular advantage except a little on the left of the bellcurve when turning sixteen fixes any health problems we may have and our siblings can patch up any we acquire afterwards."
Ariel turns to look at her in shock. "Are you telling me that you're supposed to be a baseline and you look like that? That's unfair, that is. I'm filing a complaint."
Bella giggles. "My sister's prettier, so I don't hear that a lot, but thanks. But yeah, there's gemini who look any which way except for 'with chickenpox scars and scoliosis' type values of any which way."
"Never let me gaze upon your sister then, I'd probably combust. I'd hate to go the way of Semele before I even get to thwart any supervillains who aren't my mom."
"Unless there's some way to purposefully visit between dimensions I doubt you will ever get a look at Alli. And in the interest of evenhandedness, my opinion on our relative prettiness isn't universal when she's not wearing makeup or I've let her put some on me. Semele?"
"Makeup, ech. I don't know how anybody without magic has the patience to deal with that shit. If you're here long enough to learn magic and ignite your Essence I can teach you how to use cosmetic workings, they're way quicker and they work really well. Semele, mother of Dionysus, who ignited upon beholding the divine splendor of Zeus after he'd impregnated her in his usual idiom. Though the murder wasn't technically his fault, that was all on Hera. That fucker."
"...I can learn magic?" Bella asks. "You don't have to be mutated a specific way to do that?"
"The mutation makes it way, way easier. Much in the same way that Olympic athletes spend their whole lives training to be slightly better at one thing than an Exemplar-2. But you can totally use magic! I was wrong about the 'quicker' thing, actually, spells for baselines take like half an hour of chanting. But it's an option, and magic is super cool." She produces demonstrative sparkles.
"...How sure are you that fish out of water can use magic? Because unless the requirements are insanely specific, if people where I'm from can normally do spells with chanting for half an hour, I'd have expected someone to stumble on it, and no one has."
"Oh, it's not just the chanting. You have to use some magic to 'ignite your Essence', and that'll leave you as a magicky person forevermore. But you guys don't have spirits and all that, so... not so much Essence lying around to ignite."
"Wrong kind of magic can attract demons, but y'all don't have demons anyway, so I don't see that causing much trouble. And if you fuck it up it can have unfortunate effects, but if you're here long enough to ignite then you'll be here long enough for us to teach you how not to fuck it up. You're smart, you can swing it."