Invisibility Potion

The guild staff member came back a second later, placing a glass bottle with a clear liquid infront of Sarah. "Here you go, the invisibility potion was the first one that the researcher wanted tested. Speaking of, it looks like he finally arrived."

She gestured towards the door where a man a few years older than Sarah quickly entered and walked towards her. "Hi there, I'll take it that your the one that's going to test my potion? I'm so excited to see how well it works. My potion should take stealth to the next level. It should quiet your movements and increase the length of time that you're invisible. Though like most potions, it doesn't turn your clothes invisible, so you'll have to get naked and walk through town after drinking my creation."

Sarah stood there for a few moments, a blush on her face and a smile on his. "U-Um... Is there any chance that I could do a different potion? One that has a bit less nudity? The truth serum one would be great!"

"My apologies, but no. Finding people to test my potions can be quite difficult... And making it so they have to strictly follow the list helps make sure that some of my potions are tested. It's the invisibility potion or nothing, and let me remind you that this does pay very well for such a simple task."

That was something, she couldn't deny. It'd be enough for her to rent a room today then she could earn more money for supplies later... With a sigh, she opened the bottle and started to chug it down. Her body quickly becoming invisible.

"Perfect," The researcher said, "Once your done drinking, please strip. Before you ask, yes. You'll have to strip here and not in a changing room."

She quickly set the bottle down and started stripping, hoping to get naked before she changed her mind. Eventually her clothes were on a pile on the floor. A vine slowly crept across the floor, grabbing her panties and bra and dragging it across the room. By the time, Sarah noticed, it was too late to stop it.

"I'll just hold onto your other clothes so no one steals them." The researcher then squatted on the floor, his face directly infront of Sarah's invisible pussy, causing her to stumble back with a gasp. To her, she just looked naked. Though based on everyones lack of catcalls and whistles, it was clear that they couldn't see her. It didn't stop her from covering up with her hands anyways.

Once the researcher put the clothes in his bag of holding, he spoke "Great! Next, I just have to put a tracker on you. It'd be bad if you just left without me knowing after all!" He said with a laugh. "I'm just going to touch your body for a few seconds, please don't be alarmed."

He then slowly started waving his arms around as he stepped closer to Sarah's direction. Eventually his hand landed on her face. "There you are! Perfect! Just give me a second now..."

He then used his other hand and teeth to open a vial and dapped a small liquid on one of his fingers. He then moved his hand down from her face towards her back, slowly reaching her ass and slipping a finger causing a moan and a slap from her. "W-What are you doing?! T-Take your finger out of there!"

The yelling got everyones attention back on her. "My apologies, but the tracker needed to be inside of you. This seemed like it'd be the tightest area so I chose to put the tracker there. Based on how your hole feels, I was right to do so. There's nothing to worry about, the tracker is tiny enough that your unable to feel it." He then pulled his finger out.

Sarah glared at the researcher, constantly reminding herself that he's paying for her to do this and that it'd be a bad idea to slap him again.

"Great, now I'll be able to track you no matter where you are. On my map, you'll show up as a small blue dot and I can use one of my spells to detect the tracker I put inside you. I'm using the spell currently, it gives me a faint outline of your body along with a small blue glow of where the tracker is. Let me just consult my notes where quick and then we can decide how best to test the potion."

He opened his notebook, reading off a few ideas he had. The original was her for to go streaking for 24 hours and to offer a prize to anyone in the tavern who mentioned to capture her. There were plenty of more ideas though. An examination to make sure the potion didn't have any negative effects, a series of yoga poses to make sure every part of her is covered, a series of spells being used on her to make sure the potion doesn't become undone, and more.

"Oh, which would should I have you do first?"