This might not completely fit but I thought this was a cute idea so I wanted to try writing it. It's completely ridiculous but I think it's also adorable.
"I'm sure it's completely safe, you said. I'll be able to handle it if anything went wrong, you said. I don't have anyone else to experiment on so you'll just have to suck it up, you said." Conan repeated to Haibara as she rolled her eyes.
"I will be able to fix this, it's not permanent. You're just exaggerating the seriousness of the situation, at most it will last two days." Haibara reassured despite being barely able to keep herself from laughing. "And I technically didn't lie, you aren't injured. It's nothing I can't fix even if it did go slightly wrong and I really don't have anyone else to try these things out on. Besides, you agreed that it was a worthwhile experiment to try out under the condition that I made sure you were not hurt."
"You call this not at all hurt?"
"It'll go back to normal. I also thought you agreed that it was a good idea to do some experimenting into how we shrank in the first place."
"I guess I did…" Conan trailed off as Haibara continued watching him with observing and curious eyes, the eyes of a scientist who found something that interested them.
Both child-teens broke out from their discussion when they heard the front door open. Haibara quickly hid Conan and went to see who it was. As she peaked into the hallway she noticed that there were two people there who she absolutely didn't want to come.
"Subaru-niichan, Amuro-niichan… Why are you here?" Pushing down the familiar feeling of panic that made her want to run when they focused their attention on her she gave them her best I'm-just-a-cute-little-girl smile and waited for their answer.
Amuro smiled when he saw her and answered. "Actually we came to look for Conan-kun. Mouri-sensei wants to talk to him and Ran-san said that he was coming over here to work on a project with you."
Fighting off her desire to fidget or run Haibara gave them a regretful look and met their eyes. "I'm sorry, you just missed him. He was here working on a project with me but we finished all we could do today so he left to get something to eat. I'm not sure where he is, I'm afraid."
"...I see." Subaru answered then looked to Amuro. Based on their body language it was clear that they didn't believe a single work Haibara had just said to them. Not her calm expression or cheerful voice or the actual meaning of what she said.
"It's fine." Conan's voice surprised Subaru and Amuro into giving a slight jump, having not felt the boy's presence anywhere. "You can trust them, just take me out and we can explain some of what happened."
Without turning to the direction of the voice Haibara pursed her lips and checked. "Are you absolutely sure? We can't explain most of this to them."
Subaru decided to cut in, "We don't need all the details. Mouri just wants to know that Conan is alright before he goes on the case. Our plan was actually to take him to a festival so he isn't worried about but if there's a problem with that we can change our plan."
Hesitating for a moment Haibara finally sighed and reached into her jacket pocket. She pulled out something with cupped hands so that the two men couldn't see what was inside before she brought one hand down and let them see what was inside.
Conan drew a big gasp of air having finally gotten the wall over him off and leaned back, sitting up against Haibara's thumb.
"Eh?" Neither Subaru no Amuro made any reaction for a second as their eyes became wider and they looked around to see if this was a joke.
It wasn't. Conan really was now about the size of a baseball and was resting in the palm of Haibara's hand, wearing doll clothes that was still a bit too big.
"Uh, hi. I'm afraid I won't be able to show up in front of Kogoro but I can probably make a call or something since my voice has stayed the same. Guess this probably isn't what you thought would happen when you came so you might want to rethink your plan."
"...For now let's call him and let you talk to him." Amuro finally suggested allowing everyone else to snap out of the odd field of tension that had formed. Despite not having any idea what had happened Furuya Rei and Akai Shuichi were both seasoned genius investigators, they could handle something like this… probably.
Hesitantly reaching his hand out Subaru watched as Conan jumped from Haibara's open palm into his. The first thought that crossed his mind was how efficient it would be to use a genius this size as a spy on the organization. He would fit as a doll and be able to move around independently if Mizunashi Reina brought him.
Immediately after having that thought he regretted it. As smart as the boy was and as multi skilled or inventive as he would be in an emergency he was still a civilian. A teenage boy who was now a three inch tall six year old.
When did his life get so weird?
Conan called Kogoro and explained the situation to him. The situation meaning that he ate something Hakase was messing with and wasn't going to be able to go to the case. Apparently whatever he ate made him extremely tired so he was going to need constant supervision rather than an adult more focused on a murder case.
After grumbling about it for a minute Kogoro asked Amuro and Subaru if they could take Conan to the festival nearby and watch over him. According to him the festival was likely to be heavily guarded so there was no chance of Conan attracting another murderer and it would be a great place to get food from.
Neither Subaru nor Amuro could object as it would ruin their disguise of kind, mild mannered and eager to help citizens. While Furuya and Akai might be different Subaru and Amuro would never refuse an offer to help such an important person with such an understandable problem.
They considered leaving Conan at the professor's but Haibara would need to go check on the Hakase soon and their trip would be more believable if they took a picture. At the very least they would be able to mimic the idea of Conan being normal sized if Kogoro was only looking through their pictures.
As it turned out Conan fit almost perfectly into the jacket pocket of Subaru and Haibara was able to prepare a doll sized winter coat for him to take.
"Careful! Don't drown in a cup or fall down a storm drain Conan! And try not to be eaten by any animals while your out tonight!"
"She's enjoying this way too much considering that it was all her fault to begin with."
"Don't be like that. She's just trying to be positive for you to make the whole situation seem less bad."
"Yes. I'm sure she only has your best interests at heart right now. You are, after all, her only test subject."
"Both of you are included in the 'having way too much fun' category." Conan declared to Subaru and Amuro's teasing. It really didn't feel fair to him when they used the personalities of the disguises he created or worked with against him.
Time to start the festival.
I'm planning on continuing at some time but I'm not sure when. I know this isn't at all realistic but could you imagine a pocket sized Conan? SOOOOOOO CUTE!
