Full Summary:

Chiral (adjective): Something that is asymmetric in such a way that it cannot be superimposed onto its mirror image.

In which Zim actually is just a sick kid with a skin condition, but Dib is still utterly convinced that he's an alien.

Being called an alien was nothing new to Zim, but he found that with Dib, it could sometimes be fun playing along with his delusions. It was refreshing, having someone see him without sickening amounts of pity, having someone see him as a superior being, someone to be respected and feared. Most of the time, at least. Because Dib believed the game they were playing was real, didn't know when to stop or let up.

"He's an alien! How is no one else seeing this? Green skin? Weird ears? He's obviously come to take over the Earth!"

Zim's face started to burn as the other kid ranted. Of course this new school wouldn't be any better than the last. Of course. It had been stupid to ever hope otherwise. They were already accusing him of not even being human, just because he happened to look different. Memories of taunts echoed through his brain as the kid continued talking. Freak. Weirdo. Pathetic. Crip. Alien.

And everything had gone so well this morning. He'd woken up with more energy than he'd had in days and only a mild headache. He'd even managed to eat almost all of the breakfast that his parents had made. His parents, who, for once, had actually been home, ready to see him and Gir off for their first day at their new school with a hug and kind words (and sadness in their eyes, but that was okay, it was fine, so long as his parents were actually there with them, and not off at some stupid conference. It didn't bother him that not even his own parents could look at him without that stupid pity in their gaze, nope, didn't bother him at all). And of course, he was going to meet with one of the greatest scientific minds of the century in a week. (Sure, it was so that the Professor could try and find a better treatment for his illnesses, but it was a face-to-face meeting with the great Professor Membrane nonetheless!) The day had started out so well, so naturally, it couldn't last.

"I'm not an alien. I'm just sick. So would you shut up?"

"Yeah, shut up, Dib! You're being an idiot." someone piped up from the back of the classroom. At least someone here was on his side.

"You may have fooled the rest of them, alien scum, but you won't fool me! I'm Dib Membrane, hunter of all things paranormal, and I won't rest, won't stop, until you and your evil plans are vanquished, once and for all!" the other boy declared, standing on his desk as if he was expecting the background to change to one of a waving American flag.

"Wait. Membrane?" Zim blurted out.

The other boy paused, confused. "Yeah? What's it to you?"

Zim considered his words for a moment before replying. "Nothing."

If the other boy really was related to Professor Membrane, it was probably best that Zim didn't mention the reason why they'd moved here, considering how Dib had practically declared Zim his mortal enemy within the, what, five minutes they'd known each other?

Zim went back to the worksheet in front of him, having already chalked up the idiot kid as nothing more than an annoyance and trying to figure out where this new school was in their curriculum compared to his old one.

"Hey. Hey! Don't you ignore me! You think you can just lead us all into intergalactic slavery like lambs to the slaughter? Well, I, for one, am not sold!"

"Sit down, Dib. If you interrupt the class one more time, you'll have detention for a month cleaning out the basement."

Dib paled at that and muttered "Yes, Ms. Bitters", seemingly mollified.

After that, he didn't say anything out loud, but no matter how Zim tried, the subsequent glares proved impossible to ignore.

The new kid was an alien. Dib knew it. He just knew it. He didn't know why no one else could see it. The alien (Zim, he thought his name was?) had almost his entire body covered up, and wiped down everything before touching it, obviously afraid of 'dirty Earth bacteria'. He had green tinged skin, metal where his ears should have been, a weird round thing sticking to the side of his head, and a radio antenna protruding from one of his 'ears'. Did Dib mention the green skin? It was plain as day that Zim's claim of being 'sick' was a hasty cover-up that only Dib was smart enough to see through. No one had believed him, just like every other time he'd tried to reveal the truth of the world. However, though he was still smarting from the jeers his classmates had thrown at him, Dib knew that this time, things were different. This time, things would finally change. This time, now that there was actual proof of the paranormal sitting only a few desks away from him, he'd finally be able to prove that he was right about everything all along. He'd foil the alien's Earth-conquering plans and reveal him to the world, and finally, everyone would see that they'd been wrong to doubt him. Dib Membrane, savior of humanity. It had a nice ring to it, he thought.

A/N:

Inspired by The sick human Zim AU by MLHmoo

Art by Stargazer233 on Tumblr

Even though I'm disabled myself, being deaf and having cochlear implants, I'm not chronically ill, so if I get anything wrong about any of Zim's illnesses or the general experience of being chronically ill, feel free to let me know!
I hope you guys enjoy the fic, and I'd love to hear your thoughts!