Everyone thank @starkerlover for suggesting ghost!Peter and human!Tony because that is a cool idea!!
*
Tony is aware his house is haunted, he's tested it, retested it, started fucking inventing technology to detect it and he knows he has a ghost. Bit of a boon to his atheism he supposed since an afterlife exists even if it's clearly not heaven, so at least he was still right that the Christians were wrong and he'll take that.
Point is he has books full of instances of odd occurrences he's learned to figure out how to track reliably and in repeated instances. He's absolutely established primitive contact with some kind of ghost and he's almost impressed the dead guy has a sense of humor. Problem is he can say all this till he's blue in the face to basically anyone and they'd find him nuts, and if he weren't him he'd also say he was nuts.
So for now he goes it on his own, figuring if he's going to scientifically prove the existence of ghosts he might as well figure out a way to make them visible to the human eye.
*
Peter is so bored of being dead, people can't hear him when he talks, can't see him when he moves, and whenever he tries to interact with stuff it does weird things like fly across the room or randomly short out if it's electrical. He really felt bad for the tech genius that moved into the apartment he died in only to spend probably about a year doing every diagnostic he could on every hard and software issue he could think of and it turned out he could think of a lot.
He actually really likes Tony, he's funny and smart and Peter has learned a lot watching him do everything he can to try and counteract his effect on the technology Tony relies on for almost everything. He died ages ago before the building got totally refurbished and he's super mad about all the cool stuff he didn't get to see while he was alive. Tony's set up is basically sci-fi to Peter and it's cool as hell. Tony has heated bathroom floors, Peter would have killed a man to have never experienced the feeling of cold tiles under his feet.
The best thing about Tony though is eventually he realized his technology wasn't the issue, something was interfering with it and that's when he started getting creative. Of course he has no real idea Peter has been cooperative this whole time because ghosts don't seem to be common and he's been alone for a long time, he misses talking to people and Tony is funny and laughs at his jokes when he manages to actually influence their current rudimentary communication system.
As far as Peter's concerned the progress may not be much, but it's more than he's gotten since he's died so he mostly ignores how frustrated Tony he's when most of his efforts fail. He's fiddling with something connected to a small screen that doesn't look particularly special to Peter but he knows Tony thinks it'll help him see Peter. He's used to this to some extent, people noticing he's there and trying to establish contact but no one has been as methodical and diligent as Tony about it and even then most things he's tried haven't worked.
He genuinely expects this time to be no different when he waves his hand in front of the small camera in the frame of the screen. It's almost more for the amusement of watching his hand disappear from view under the camera than to test Tony's latest invention but when he sees his hand he swears he remembers what it's like for his heart to skip a beat.
*
The first time Tony saw his ghost on screen he's somewhat embarrassed to admit he acted like a character in a horror film and jumped out of his damn skin. By now it's fairly normal even if it's fucking irritating not to be able to hear the kid babble like he obviously constantly does. So far their sign language lessons have been working but teaching a ghost a whole new language is only so efficient, so he's been working on a way to hear Peter talk.
Fucking unsettling to read about the death of a 17 year old kid of influenza of all things, but it seems pretty obvious that being dead didn't exactly stop Peter from keeping track of the living. He's funnier with a consistent visual and at least has a natural flair for the dramatic that lends itself to using sign to communicate even if Tony would still prefer to hear Peter, since he's confirmed Peter can hear himself.
Peter is attempting to babble in sign, not able to move his hands fast enough to keep up with his thoughts and occasionally failing a translation from English to ASL and Tony finds it endearing all the same. He's been working on what he thinks a spirit box should have been instead of that god awful noise making machine that even Peter hated enough to kill it with whatever ghostly trait screws with technology and confirmed as such later.
It's been months of testing and the progress has been snail paced if that but thankfully for him Peter is always talking, so if he's going to capture his voice it shouldn't be hard to know when he's managed.
"-And I mean honestly what kind of ghost torture is sticking me in a house with someone this hot when I'm not even corporeal-" Tony's jaw drops as he looks over at the screen Peter is occupying, Peter's voice cutting out as he seemed to hear himself too.
Tony snickers, "you're not the first or the last one kid, no need to look so embarrassed."
*
"Oh my god that's what you guys call interior design these days? It's so ugly, back in my day we actually knew what colors and patterns were," Peter says, shaking his head at Tony's living room.
Tony rolls his eyes, "don't make me regret these glasses," he tells Peter like he'd have ever gone without the ability to see the whole fucking ghost occupying his house in a regular basis. Glasses made to be smaller versions of the screen he originally built to see Peter with was a natural solution.
"Why does your furniture look like geometric blocks this is terrible I was poor and even I lived better than this," Peter laments, giving Tony's perfectly fine couch the side eye.
"Do you always have a habit of commenting on the dwellings you died in?" Tony asks, raising an eyebrow.
Peter snorts, "what else have I had to do for like, 95 years? I've had some cool people live here too, I miss the lady with the shag carpet and little dog. And that teenage girl who liked rock bands, I wish I could have listened to that stuff when I was alive. And that guy with the turtle he was cool, terrible taste in TV if you ask me, but he at least had some color on his furniture. This looks like a sanitarium," Peter says, gesturing around and Tony makes an offended noise.
"It does not look like a hospital!"
"Then why is it so depressing? Are modern people allergic to personality in their homes? Face it Tony, you need a ghost to help you decorate because being alive definitely didn't help you any," Peter says, nose in the air.
Little asshole, but Tony gives him a fond grin anyway. "Keep going and I won't bother inventing a way to feel you."
Peter's eyes go wide, "you think you can do that?"
Tony shrugs, "well, two years ago I couldn't see or hear a ghost and now I can do both. Might as well test the limits. And you're always going on about how hot I am," he points out, delighting in the way Peter's cheeks turn red because apparently ghost completions work the way they did in life.
"You promised me you turned those spirit boxes off sometimes! How often do you listen in?" he asks.
"I never actually turned them off," Tony says, earning a deeply offended noise from Peter. "And before you bitch about privacy I'll have you know I know that you spy on me all the time."
"I'm a ghost Tony, what else am I supposed to do!"
