[Slime TF, Brain Drain, Incest]

She had done it! She had finally done it! She had made the ultimate, most brilliant potion in all of existence!

But what was it? And who was she, for that matter? Why, she was the greatest and most mad scientist on the planet! She was Lily Lovelace! The one who had made the love potion! The one who had concocted magnificent brews that could make your wildest dreams come true!

And this potion would further that reputation! Because it would turn the solid form of the one who consumed it into a semi-solid slime-like form, allowing them to traverse into places that liquids could without losing the ability to stand up! It was a brilliant invention!

...But her brother, Joyce, wouldn’t help her test it out! Hmph! And to think that she would give him so many gifts out of the goodness of her heart, and definitely not because she had some sort of budding feelings for him. This is how he repays her for all of this?

Sure, he told her that he was sick and tired of being transformed all the time due to the fact that she ‘invaded his sense of privacy’, but what was that if not an obstacle for science to develop!? He was going to talk to her again at some point. And then he’d feel sorry for what he had done!

...H-he definitely would. Otherwise, she wasn’t sure what she was going to do. A lot of what she had done was ultimately just to show somebody that she had been brilliant, but…

“Enough of that!” Lily shouted at herself as she swirled her slime solution around in its flask, huffing and puffing as her adorable pink twintails blew around from her emotions blowing out of her head. “I don’t have time to dwell on that stuff, he’d probably get a kick out of me being this worried about somebody for the first time in my life. And I’ll be damned if I give that brat something to be happy about, after he blew me off like that!”

Without any more hesitation, the brightminded girl dumped the entire concoction down her mouth, gagging a little because the substance was very thick and viscous. She didn’t even think about the latter before it was too late, prompting her to wince and writhe a little as she swallowed more and more, hoping to just get it over with…

One cough and a sufficiently sticky throat later, her stomach was now full of the substance. “Note to self. Remember to make your next potion more liquid-y. No wonder he hates drinking my potions.” The pink-haired genius muttered as she slowly but surely got back up after collapsing thanks to the pains in her throat.

The results were surprisingly quick, as Lily looked at her hands to see them turning translucent. It was working! “As expected, my genius knows no bounds. If only that brat saw me now, succeeding even without him!” She cried out, giggling as she adjusted her rather oversized glasses. Oh, she loved the feeling of success…

...Hold on. There was something wrong. How could she tell? Well, that was simple for a genius like her. That, and her hands were definitely a lot sleeker than they usually were.

Now, for all of her insight into the development of science and all that junk, she knew that she wasn’t the prettiest girl around. Her lack of personal hygiene unless otherwise necessary meant that her body looked like it lacked a lot of oomph. She wore no makeup, only really putting her hair into the usual twintails because they brought her good luck. (and because her brother told her that she was pretty that way but she wasn’t going to say that to his face!)

So why would a potion, designed to make her just turn into a slime, end up making her prettier? That wasn’t at all in her calculations. What had she missed? Why was she turning into a pretty slime, when that wasn’t at all something she needed?

...Hold on. Hold on…

Lily blinked a couple of times as she looked at herself, then looked at herself in the mirror, before giggling a little. “I’m really pretty…” She chimed, her usual harsh voice sounding a lot brighter than normal. Even though most of her body had turned bright pink like her hair, to the point where you could hardly tell where her hair or her body ended with how both had turned into one big lump of slime.

Now, if she had bothered to double check her research, like she always did after experimenting on her brother Joyce, she would’ve realized where she went wrong. Slime girls, which were the basis for this concoction, actually had a cap on their intelligence. If they went over it, their body would use the excess to expand rather than put it to use for thinking.

Even though she could very clearly see her body growing, thickening by absorbing the smarts from her head, she could only barely comprehend what was going on. Because the sight of her form looking as cute and as pretty as it did was enough to distract her quickly stupifying sense of self.

“Lily’s reaaaal cute!” Lily giggled, stretching a little, watching her body grow and grow without a care in the world. Oh, it felt really nice. It was like something bubbling out across her entire form, making her look a lot nicer than she ever had before. Sure, she didn’t have toes. But what were toes good for, anyway? She liked having a puddle for feet.

Of course, the more she grew to look her proper age, the more she had to fill out. Her formerly miniscule chest pushed out and filled out until those things were a nice H cup, while her rear and hips were now on the verge of perpetually clapping thanks to the jello-like nature of her form.

And as she felt the pleasure of her body playing with itself as a result of her idle vibrations, her draining mind focused on a single thing. A single boy, that she should’ve been so focused on for a while…

Her dearest brother! Little Joyce! Oh, he was still mad at her, wasn’t he? He was going to be so mad when he saw her, but that wasn’t fair. ‘cuz she loved him! She loved him lots and lots! Ever since the two were kids, he always helped her out. Even if he didn’t like it. Because he knew that she needed him, and that was why she always tried to help him out after!

Lily let out a sigh as she started leaving her room. Leaving allllll of her equipment, her clothes and even her glasses, just strewn around in the room as she headed straight for him. Because she needed to make sure that he knew that she loved him!

Joyce had shut himself inside his room. And even as she knocked on his door a couple of times, he didn’t answer. He was still mad! That’s sad! She should say sorry, and like, make sure that he knows that she really does mean it this time. She’d never do it again!

She didn’t let a door stop her. Even if she rammed into it a couple times, thinking she could just open it that way. Once she realized there was a hole, she sank into her puddle and quickly erupted on the other side. “Jooooyce! Big Sis is soooo sorry!”

Joyce, the redheaded boy that she had experimented on so many times before, was initially angry as he heard her voice echo through his room. “How’d you get in-” He instinctively complained, before he looked at her.

The boner that he immediately popped in his pants was not one that he expected to get anytime soon. Neither did he expect to see his sister in such a gelatinous form. “W-What? L-Lily, what the hell?!”

“Eh?” Lily replied, before looking at herself. “What’s wrong?” She asked, tilting her head as the added gravity caused a few droplets of her semi-solid form to drip onto the floor below.

Joyce got out of bed and grabbed her by the sides, still shook but not enough to be frozen. “You’re a slime, Lily! What did you do!?” He shouted right at her, the look on his face clearly spelling out his worries.

“Oh! Well, I wanted to do a thing, but then you were all mad, and I had to do it myself!” The pink slime girl giggled, before slowly wrapping her arms around him. It was nice to have him this close…

Maybe a little too close, as she felt her body pounding against him. Oh, he was so cute… and she still needed to apologize for making him mad.

“Okay, listen, we have to turn you back. You have to have an antidote, like all the ones you’ve used on me-”

Joyce’s attempts to reason with her were cut off as she collapsed atop of him, the curvaceous slime giggling as her breasts hung in front of his face.

“Ssssh, Jooooyce…” Lily licked her lips. “Big Sis needs to apologize for eeeverything she’s doooone…”

And apologize she did. With her whole body. An apology he accepted, after a lot of ‘convincing’.

Did she change back? Of course not. She was too stupid to at this point. But that didn’t matter. Because she had something that was much more important to a girl like her.

Her dearest little brother’s love!