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 my," Morty says faintly.
The teenager places a paper cup under a tap and pulls a lever, producing a quantity of blood which flows into the cup. Once the cup is mostly full the teenager caps it with a plastic lid, conscientiously tags the "blood" bubble on the "this drink contains:" section of the lid, and slides it over to Mark with a bendy straw. "Thank you, come again," he drawls.
Peter is sitting with a young woman with strong facial similarities to someone Mark knows! She spots him and waves a fried drumstick of absurd size.
Mark approaches warily, sipping from his cup of cow blood. Maybe this won't be completely terrible. (Who is he kidding. It will be completely terrible.)
She sticks out a hand. "Hey! I'm Ariel, codename Stormhammer. Peter tells me you're a vampire from space. A spacepire, one might say. This intrigues me."
"Mark," says Mark. "No codename. Not from space, either. I grew up on Earth, just not this Earth." He eyes her hand nervously and doesn't touch it.
"Hang on," says Ariel. "Fubar's pinging- uh- holy shit, what?" She turns away from Mark to focus on the mental conversation.
"Soooo, first of all, sorry about- basically everything about this. Second, holy shit. Third, d'you want an alternate-universe-girlfriend hug?"
Hug. Ariel is slightly cooler to the touch than the average human, but she is practiced at hugs.
By some miracle, he does not break down crying. He just hugs her. Non-crushingly, even, since he doesn't have clear information about her fragility relative to vampire hugs.
Oh, fuck it, there he goes with the silent tears. He puts down his empty blood cup so as to cling to her more effectively.
This is not an entirely unexpected outcome! Ariel continues hugging and makes kind sounds.
Mark is such a fucking mess. He does not understand why these people like him so much. Now there's two of them, even. And they live in different universes. Which means he is always going to be missing a minimum of one person he is atrociously in love with. No wonder he's crying all over her in the middle of the cafeteria.
Well, nobody who knows what's good for them is going to judge; Ariel is known for uncompromising destruction in defense of small emotional men. And various other persons.
"Man, don't apologize for feeling things. You have had the shittiest day of all shitty days. 'Sides, crying on me isn't even a problem, I don't get mucky or anything. Benefits of a TK shell and superhydrophobic clothes."