Which finds him in a room heavily decorated in Halloween kitsch, with a pair of highly startled teenage girls, one of whom drops the piece of chalk she was using to draw a highly ornate mostly-circular design on the floor.

Cam looks around. "Didn't anybody ever tell you not to draw on the floor?"

"No! Nobody told me that. I don't see how random floor doodles constitute an invitation to random teleporters anyway."

"...Didn't anybody ever tell you anything? I'm a demon. You summoned a demon."

"I get told lots of things. More than you, apparently, what abusive hyper-religious family decided to tell you that a tail and wings made you a demon?"

"...Excuse me? It's a purely technical term. It'd apply even if I didn't have them."

"Technical term for what?"

Cam sighs. "Okay, Daeva 101. There are three kinds! Angels change, fairies move, demons make. If you draw on the floor in the right, or in this case wrong, way, one may appear! Daeva are passing acquainted with economics and the ones who show up to summons are interested in engaging in trade with you! As a general but not absolute rule demons are the ones with bat wings, fairies are the ones with bug wings, and angels are the ones with bird wings, but if you get a jokester you might find angels and demons with any kind or any of the three with no wings at all. Other cosmetic features vary, although I will have you know my tail is very fashionable. Also, drawing on the floor when you don't know what you're doing is insanely dangerous and if I were so inclined I could already have destroyed this planet, so, you know, don't do it any more, but I'm a nice demon and as long as I'm here do you need any stuff made?"

"My dad could probably destroy the planet if he really put his mind to it. I've never heard of a daeva before in my life. Why the hell should I believe you aren't just some random mutant playing pranks? Because if you are, the Xavier Institute was one of the most idiotic places you could possibly have picked for it."

"...My probability that you're Amish and that's why you didn't know what you were talking about has declined."

"I'm Jewish."

"And last I checked Jewish people as a group did not tend to form little communities of people who do not tell their children that daeva exist! I mean, I think the ultra-Orthodox have a lot of rules about summoning us, but that's not the same thing as 'a winged man has appeared in the middle of a circle I drew on the floor, what could possibly be happening'. So, uh, where the hell am I? Or when. Time travel would also explain this. You're speaking English, which is something..."

"The Xavier Institute, Westchester, New York, 1980."

"Time travel! And possibly also alternate universe, if you have an explanation for me that isn't 'I'm a demon'. But you have a New York, so not that alternate. Is there such a thing as Finland, exactly one moon, cheese danishes, etcetera?"

"Etcetera, I would assume so. Are you saying there aren't mutants where you're from?"

"I mean, do you mean polydactyly and trisomies and intersex conditions, or do you mean 'fully functional, snazzy-colored, matching set of wings and a barbed tail', when you say 'mutants'?"

"I don't think I've met anyone with both wings and a tail in particular, but yes, that one."

"Yeah, we don't have those. I could put wings and a tail on a human but by far the most conservative explanation for me back where I'm accustomed to being summoned to is that I'm a demon."

"And being a demon gives you teleportation abilities...no, you said I summoned you by accident."

"Right. I can't teleport. Even fairies can't do that, they can just zoom around real fast."

"I'd probably be more skeptical of your story but you don't really feel like a mutant anyway."

"Feel like one? We are not so thoroughly acquainted."

"I mean your mind isn't shaped like a mutant's. I'm a telepath."

"I'm not reading your mind. I'm just observing that it exists, and I literally couldn't stop doing that barring what amounts to torture."