An engineer, a beautiful researcher, an oblivious best friend

You walked around the perimeter of the machine, eyeing your distorted reflection in the polished metal. It seemed crazy, this idea that you could just vanish into ethereal vapor and... then what? Haunt Emilia's mansion for a day? You'd worked six years as a test engineer for a hardware company, and that must have had some weight in Miss King's decision to bring you down to her mansion in the first place. If she wanted to just observe the effects of the machine, any average person would work just fine, and would probably serve as a better psychological experiment than anything. Sure, if the machine worked as you were imagining, you would have a hell of a great time with it! A ghostly form would provide the perfect opportunity for pranks and stunts on your friends that they'll never be able to top.

Out of the corner of your eye, you saw your favorite target for such shenanigans. Chase, perhaps your best friend, leaned against the doorframe leading into the room that housed the Ghost Machine. He didn't know why you and he were in the mansion, but he didn't care enough to ask, instead trying his best to spark a bit of small-talk with a gorgeous redhead standing next to him. Yyou knew the chance he might actually ignite conversation was slim to none. Tall and lanky and with a mess of sandy hair, Chase fancied himself as a charming nerd, while in fact he was just a run-of-the-mill nerd. You didn't mind the endless conversations he sprang on you about the latest balance patches to his favorite games or whatever, but in no world did the woman next to him care about any of it.

You'd have felt sad for him, but she was so far beyond his league they might as well live on opposite planets. Long orange hair tied up in a ponytail, beautiful brown eyes, and a light dusting of freckles summed up her cute face, giving her a friendly and personable vibe... although as Chase's verbal onslaught continued, her expression soured slightly more with every word as she tried to hold her composure, it's honestly surprising she had yet to walk away. That act in itself might be a sight to behold, as opposite her cute face with its disarming smile, her body came armed with dangerous curves that seemed intended for some other head entirely: long legs that swelled into impressive hips that disappeared underneath a tan skirt, a generous bust hidden behind a tablet that she hugged to herself, but you'd taken a long glance at the expansive cleavage earlier when she'd tried to pretend to do a little work in an effort to escape the one-sided word barrage aimed at her.

Gosh, what if... oh, a devilish thought crossed your mind.

It'd been too long since you last pranked Chase. And if this machine worked as intended, how funny would it be to make a beautiful, incompatible girl like her ask him out on a date? And then when you show up instead of her at the fancy restaurant... it might be a little mean, but you'd at least pay for the meal to make it up to him. You knew he wouldn't get any further than that on his own, for sure.

"So what else is expected of me if I 'go ghost'?" you said, turning back to Emilia. "For the pay you're offering, there has to be more tasks and parameters than what you've told me so far. I'll push any boundaries you want, I'm good at that part of my job, but I need to know which way to push."

The frail woman next to you smiled, propping herself up further on the railing beside you. "Perceptive. I knew I'd like you. You're correct, this job is more than just touching the machine and reporting the effects, I've already gathered plenty of data on that aspect. Instead, when you have 'gone ghost', as you put it, I wish to know the bounds and limits of organic interaction and manipulation via an ethereal entity."

You quirked an eyebrow. "That's a fancy way of saying possession."

"It is. But I need data on more than your ghostly capabilities." Emilia turned toward the doorway, calling out to a particular redhead. "Skyler, if you'd be so kind as to join us?"

One gigantic sigh of relief later, the beautiful Skyler strolled forth. The hypnotic sway of her hips as her heels clacked against the marble floor nearly made you forget all about your impending job, but once she came to a halt next to Emilia and caught the billionaire's smirk out of the corner of your eye, you remembered your manners and stood upright again.

"I thought you'd forgotten about me," Skyler said to Emilia, before offering you a smile and an outstretched hand to shake. "I'm Skyler Lawrie, you must be Wesley? From what I understand... I'll be your adversary."

"Adversary?" You glanced between the two women, from Skyler's friendly eyes to Emilia's, where a hint of a scheme brewed behind those irises.

Emilia nodded. "Skyler here is an accountant by trade, but she does some paranormal research on the side, that's how she caught my eye. No reputable science journal would dare publish a paper on 'Psychic Harmonics to Disrupt Supernatural Influence', but that's why I make sure my staff check all the disreputable ones, as well. Most submissions are scams or pure imagination, but Skyler has a quantifiable hypothesis about disrupting ghostly possessions that we can actually measure. We tested her technique using a subject that took a naive approach to possession and control, and she bested them every time."

"They kept trying the same thing over and over," Skyler said, turning her tablet around to show a video of a spectral being entering Skyler's body before being ejected a minute later. Each time the being possessed her, she expelled it faster and faster from herself until on the final attempt, the ghostly entity just bounced off her like a balloon against a wall. "I thought that was enough proof for my technique, but Emilia insists we explore more angles with someone who could be more... creative, I guess? To see where my technique has weaknesses or if it can be bypassed. You find the gaps, I work on how to close them."

"So, hold on." You rubbed your forehead, needing a moment to process what the ladies before you were hinting at. "If I'm getting this right, you... I'm... I'm going to be pen testing your body?"

Skyler blushed, glancing away. "Well, I wouldn't put it quite like that, but..."

In contrast, Emilia's smirk only widened. "That's essentially correct. As a ghost, of course. We want you to design various methods of entry and manipulation with Skyler as the target host, and whatever barriers she puts up, you are to seek out any ways to circumvent them. Except for anything physically harmful, you can make whatever attempts you like within a six-hour window each week followed by thorough documentation of your techniques and results, what works and what doesn't. You can try the straightforward possession technique, or try to sneak into her when she's unaware, or try to scramble or trick her mind, on and on. There's just one other catch to be mindful about."

"And that is?"

"Since we'll be using the machine's strongest setting, you'll be a ghost for days at a time throughout this experiment, and if we need to we'll extend the trials indefinitely as long as we're continuing to get good data. Your pay is guaranteed for the month even if Skyler bests you in the first session, but I'm prepared to expand the research if we get good data on the strengths and weaknesses of her technique. That said, as part of the deal, it will be four sessions minimum in the month, six hours of attempts during the workday, two hours for Skyler to do her own write-ups on the events and observations of the previous session, followed by allowing you full access and control to her body for the remainder of the day with no resistance. That's when you'll take care of your own writeups, but then after that, what you do on your time is up to you."

You glanced to Skyler, who nodded in affirmation, although a blush became apparent on her freckled face. "Again, no physical harm, but... yeah. Emilia suggested it so you and I could observe what the end state would be like if you 'won', which might help us both with our evolving, uh, strategies. If we both know what the end result is like, we can probably work backwards in some cases. I'm... prepared, though, for you to do anything you'd like."

Anything you'd like...

Ignoring that you had no idea what you were getting into with testing possession of someone familiar with anti-ghost techniques, and that you'd have to get used to being in the body of a beautiful woman for a day a week, and that the whole project sounds like absolute lunacy that would probably hamper your career if any legitimate company found out about your participation... you could think of some fun to do with that time. You glanced to Chase, still by the door, tapping away at his phone. Your devilish little plan might actually get some legs... and while Skyler might not be fond of the result, it sounded like wouldn't get in your way.

The pay would be nice, but it wasn't the source of the conflict in your mind. All you could think about was whether days at a time as an ethereal entity was worth pulling off the most elaborate prank on your best friend.