Zim picked up one of the many unlabeled vials suspended in front of him. He took his time in removing the cork while he recited his well-planned monologue to his archnemesis.
"Dib-stink. I have devised an ingenious concoction that will make your head lighter than air!" He turned to face his captive. "You're going to be a helium head for the rest of your life!"
"A helium head!?" Dib's pupils shriveled. "I don't want to be a helium head!"
"Oh, but you'll be much worse off," Zim casually strode up to Dib, "If you resist."
Dib struggled in his bindings, but he couldn't seem to houdini his way out of this one. Zim brought the vial up to Dib's mouth, and Dib retaliated the only way he could think of. He turned his face to the other side, so that Zim was nudging Dib's cheek with the vial.
"Oh come on, stink. Don't be that way." Zim berated. "You don't want to know what I can do to your cells."
"What— What can you do to my cells?" Dib asked in a mixture of pure fear and genuine curiosity.
"Well... have you ever been in a constant state of dying?" Dib visibly cringed away from Zim at this point, while Zim just leaned back on his heels with a smug grin. "It's a little like that."
"I— I won't be a helium head! You'll never see me concede!"
"Looks like you're a little late on that one, earthworm." Zim said. He was still trying to feed the human the contents of the vial, but a mechanical arm from his PAK had taken a syringe from the counter and depleted its contents into Dib's neck. Dib recoiled from the pinching sensation.
"Please don't tell me that was the death stuff." Dib groaned, wishing desperately for the ability to rub the sore spot on his neck.
"Oh please, you're the only human with a head big enough to successfully execute this experiment. It won't kill you. Probably. Unless you, like, fly into the sun or something absolutely stupid like that." Zim laughed.
Dib recoiled in fear, squirming to be released from his bonds. Zim glanced at them, only vaguely wondering if he should release his nemesis. Eventually, he returned to his desk, primarily to grab the key to the bonds. But as he was going to grab the key, his palm passed by a syringe sitting in front of his keyboard. "I thought...?" Zim muttered, he held up the syringe, peering into it to try and determine the contents. He glanced over at Dib.
Dib watched in growing fear as Zim froze and looked from the syringe in his hand to Dib. "What did you do to me!?"
"Oh— Nothing! Nothing! It's fine! Just the helium head! Nothing to worry about, Dib-stink!" Honestly, Zim had no clue what most of these vials actually contained, and only knew the helium head one was correct because he had just made it recently. He cautiously set down the syringe, and grabbed the key. "It's been about a minute? The serum should have made its way to your brain by now. Let's see if you float." Zim unlocked the bonds, and Dib merely fell out of them, landing in a crumpled, distressed heap on the ground. Next to him, Zim noticed, lay the syringe he had struck Dib with.
Zim picked up the syringe, and peering closely at it, noticed a word scratched into the glass with what looked like a knife. "DANGEROUS"
"Ah. I see." Zim muttered, and returned to his desk. "So Dib, this is an... unexpected twist."
"What is?" Dib groaned from the floor. His head, if anything, felt heavier.
"I have... no idea what I inserted into your bloodstream. However," Zim turned around with a flourish, his white lab coat billowing out behind him reminiscent of an anime character. "We will study the results regardless!"
Dib felt like screaming. "What do you mean you don't know what you shot into me!?"
"Well the syringe is labeled 'Dangerous'"
"Oh god, oh god, oh god, oh god" Dib began muttering feverishly under his breath. "This is how I die. I'm going to die in an alien's secret lair after he inserted poison into my bloodstream!"
"But maybe it's just, I don't know, water!" Zim grinned cheekily, "Water is dangerous to me, so it would make sense for it to be labeled as such!" He didn't exactly know why he was trying to comfort the Dib, but it made the pinching feeling in his squeedilyspooch dissipate, so he continued. "You should... go rest up, or something. We've got a big week of data collection ahead of us!" Zim grinned, and Dib left the room, glaring back at Zim every so often.
The corridor that he had left led to only one room, a small, almost unused room that had an adjoining bathroom. It was clearly meant for a human. Dib vaguely wondered if it was a new addition to the lab, given how much more lenient Zim was getting with Dib coming over. Nevertheless, he was starting to feel drowsy, so he went ahead and lay down in the brand new bed, drifting off to sleep.
To both boys' surprise, Dib woke up feeling about as okay as when he fell asleep. He had a vague feeling of sickness, but he had no odd symptoms, no excruciating pain, he was 'disgustingly normal' as Zim had disappointedly put it. Dib just sort of hung around Zim for most of the next day since he didn't have much to do. All of his possessions that included a camera had been confiscated, so his phone and watch were both in a lockbox somewhere.
Zim pulled up a document on the monitor, a spam email from some Empire-adjacent shipping company. Dib let out a small laugh behind him, and Zim felt an urge to hide the email, but remembered that, to his knowledge, Dib knew nothing of the Irken language, so he was safe in that respect. It was probably the foolish earth-monkey entertaining himself with some trivial toy. He nevertheless double checked to make sure that his computer wasn't displaying the email in English on some other monitor, and once he decided that yes, he was safe, he continued reading through it.
"You bought germ goggles?" Dib laughed again. Zim spun around— he thought he had returned those! But to his surprise, Dib's eyes were scanning the email displayed on the monitor. Zim, flushing a dark green, quickly minimized the window.
"How did you read that!?"
"Why are your emails in English?"
"It wasn't—" Zim triple checked, ensuring, for the second time, that his emails had been displayed only in Irken. "It wasn't in English!"
"Well it sure looked like English to me, but go ahead, you, being a non-native English speaker, please, educate me on what is and isn't English."
"I'm being serious, earthworm. How were you reading that?"
"And I'm being genuine. It was in English."
Zim brought his gloved hands to his temples, massaging his forehead. "Why..." He pulled up a document from his computer, this time something non-incriminating. "Read this."
"It's just the alphabet, you idiot. I'm not going to read it."
Zim squinted at Dib in a mixture of confusion and wonderment. "Okay, this."
"His Royal Pasty the Pastiness requires more—" Zim cut Dib off.
"Okay! Okay! That's enough of that one." Zim pulled at his antennae, "I need to make a note of this." he mumbled, mostly to himself. He pulled out his tablet from his PAK and began writing things down. Dib, vaguely interested, leaned over Zim's shoulder to read.
'Can read Irken. Slightly nauseous but no signs of immediate cell damage. Reaper Serum? What is it!?' "What the heck, Zim?! What's all this nonsense?"
"I should conduct more tests..." was all Zim muttered, not replying to Dib. He then turned back to his computer, ordering items off of the internet and searching for clues as to what on earth was happening to his lab rat. He paused his online shopping spree, suddenly self conscious of his bookmarks and web history, and changed the computer's display language to vortian, a language he knew for a fact Dib hadn't been exposed to. It didn't matter, however, because Dib had his hands latched into his hair, curling up on the chair he had been sitting in. Zim paid him little attention and worked on ordering more lab equipment and googling his predicament.
Dib, on the other hand, was not angry at Zim— well, he was— but at the moment, he was more doubled over in pain than anything else. He couldn't describe the pain if he could. Sadly, he couldn't. His jaw was locked shut, and he was in far too much pain to do anything other than hold his head in his hands and curl up in the fetal position on the chair. The pain was absolutely excruciating, and Dib knew that if he could feel anything other than pain, he would only feel hatred for Zim.
Zim searched for what felt like hours, but came up with a thousand monies in debt and with no definitive answers to his lab rat's predicament. He looked over at the lab rat in question, who had not moved in three hours. Unusual behavior for a human, or any living being really.
He tapped the human cautiously, worried that his little rat would crumble like stone if he hit too hard. "Dib-stink?" He asked, quietly. The human didn't move.
Zim panicked, was the human dead!? Did he just waste three hours and thousands of monies on a dead man? He watched carefully for the telltale rise and fall of the human's back, to signal that he was breathing. Nothing. Zim felt like screaming, so much time and money, down the drain, and now no one to experiment on! "Computer! Run a scan on the Dib-human!"
"Scanning" the computer muttered. "Scan complete. Subject 'Dib' is in a comatose state."
Zim sighed in relief, and then paused. "Computer! Why isn't the Dib breathing, then?"
"Subject Dib is breathing." The computer said shortly. "However, his breathing is very shallow. Subject is in excruciating physical pain."
"Oh good," Zim sighed in relief. "Computer, deal with the human."
"Okay..." the computer hesitated, "Are you just going to glaze over the pain part then?"
"No! Of course not, computer!" Zim watched as a robotic arm came down from the ceiling and picked up the Dib, who remained curled up in his ball of human filth. "What kind of scientist would I be if I didn't note it down?"
"You're far from a scientist." Computer muttered. "And by the way, Subject Dib is not human."
"Not human?" Zim quirked an eye at this, "What do you mean, Computer? Run a DNA scan after returning the Dib to his bed."
The arm flew down the hallway, and moments later Zim's monitor changed from a Google search page to a screen with a loading bar. "Scanning" the computer said in his gravelly voice.
Zim watched the loading bar as it filled, and inspected the monitor once it finished.
"Subject is 75% human, 5% Bologna, and 20% Irken." The computer sounded like it was trying to keep his voice down, but Zim had little regard for that.
"WHAT?!" Zim yelled, "Computer— you wouldn't happen to know what I shot into the Dib's bloodstream, would you?"
"I know just about as much as you. You realize, Master, that this wouldn't be happening if you simply labeled your vials." Zim jumped out of his chair and began pacing around the room.
"I'll need to concoct a remedy for the solution... Where is that syringe?" Zim rifled through his things, looking for the syringe with the word 'dangerous' carved into it. "The great Zim will simply reverse engineer a cure before the Dib realizes the effects!" Zim finally found the syringe, and it looked almost completely dried out. There was about a drop or two of the solution left in the syringe. "Okay..." Zim looked around, finding an empty test tube after a few moments. He opened the syringe and emptied it into the test tube. "This'll surely be enough..."
"If you don't mind, Master," the computer began, "Why did you have a solution like that in the first place?"
"I'm... not entirely sure..." Zim groaned. "Computer, scan the test tube, would you?"
The results of the scan showed up on the primary monitor, the solution was approximately 36.5% Irken DNA, 22% Helium, 20% Sodium Chloride, 13.5% Hydroiodic Acid, 5% Carbon and 3% Water.
"Master, I hate to be the purveyor of bad news, but I think in your hastiness just now you mixed the helium head mixture with whatever it is you put into Subject Dib."
"You think I didn't realize that?" Zim felt like he was going to pull out his antennae in frustration. He placed the test tube to the side, "What should I do, computer?" Zim asked in defeat.
The computer seemed to be thinking, then he replied cautiously, "Tell him, apologise, and work together to find the cure?"
Zim glared at the monitor in disgust, "No, that won't do..." Zim thought, "I've got to keep this a secret."