This chapter was fun, and relaxing, to write. I ended up going way more in depth about a lot of Irk headcanons I have, as well as Irken biology headcanons. Enjoy!

Dib chucked an apple core into the trees. Zim heard it soar farther than Dib would know with a twitch of his antennae. He honed his hearing and picked up birds singing, squirrels foraging, and bugs soaring through the air. Dib reclined in the tree branch, letting his legs hand off the edges.

Zim sighed. The sun was warm, the wind was low, and the shade was covering his eyes. He was at an epitome of relaxation. He could have fallen asleep, contemplating setting his metal legs out to simulate a net. Dib sighed next to him, pulling him from the stupor he was in.

"Zim?"

"Hm."

"I should really show you a National park. Or a Marine Sanctuary. Or a reef. If you're staying, you should experience as much of the Earth as possible," Dib mused. Zim grunted beside him.

"Zim has plenty of time to do those things," he says. "And Dib-stink need not worry about the experience, it will always be new to Zim."

Dib puckered his lips. He swung his legs, thinking. Zim let the silence stay, preferring to fall into his stupor once more than continue to interrupt it. Dib hummed and looked thirty feet below to the ground. Gir was in disguise, sitting at the base of their tree. For once he was being patient.

"Have you never been to a planet with vegetation?" Dib asks. Zim supposed he couldn't assume that question came from nowhere, given their location. He cracked an eye open, closing it again from the light.

"Zim has, but vegetation is not uniform across planets, Dib-stink. That much should be a common, and obvious, assumption."

"Humans have never been farther than our own moon, Zim, we don't know that as a fact," Dib said with a chuckle. "THAT should have been obvious."

"Do not patronize the mighty Zim!"

Dib laughed, holding his position in the branches as Zim hit him. "Ok, but seriously. I should. I know you said Irk was converted to all metal, but do you have access to what it would look like before that? With your PAK?"

Zim sighed, holding up his hand to indicate he needed time to check. He scoured through his PAK's connected resources and Irken memory banks. The PAK swept through the archives to the earliest stored memories.

"They were…" he paused, experiencing the images in a quick succession. "…not covering the planet as they once would have when PAKs were created and connected."

Dib's eyes widened. He nearly fell from the branch as he scrambled to sit up.

"What did it look like?!" he asked. Zim flattened an antennae and grimaced.

"Dib!"

"Sorry."

Zim settled back down, sifting through the archives. "The predominant color in plants appeared to be yellow. Our atmospheric composition changed their color from the dominant green you are used to."

"Your atmosphere gave you yellow plants? Ahaha, that'd be weird to see. A yellow plant that isn't dead."

Zim smirked. "Weird for you, Dib-stink. A planet's atmosphere determines plant color, they can change on many planets. It depends on what light is let through the most."

"So, there could be red plants on a planet?"

"Yes. Some planets have plants colored in the infrared spectrum. You, Dib-stink, would not see their true color. But Irkens have superior eyesight, and Zim would be able to see colors in that spectrum."

"Wouldn't it have to be really dark for them to use infrared? I couldn't see them anyway," Dib sighs. "What about oceans? Did your planet have those?"

"Almost every planet that is habitable would have an 'ocean', Dib-stink," Zim stated, as if it would be obvious. Dib surmised it likely was a question he would have known the answer to had he given it thought. He shrugged it off.

"Whatever. Did it have any life in it? Earth's life evolved from our oceans."

"Irkens do not possess that knowledge, nor did we care," Zim states simply.

"What?!"

Zim slams his hands over his antenna at the sudden noise. "Dib-stink you will deafen Zim if you do that again!"

"How could you not care?! You literally edit your own DNA for evolutionary purposes and you never bothered to research how you got to the point before that?!"

"For what use would that have been?" Zim asks. "We needed the knowledge of where we were at the time, not before. Aside from this, it does not matter. Irk has been converted to all metal, there is little to no evidence of what was before Irkens evolved into Irkens. We evolved, we modified, we conquer. That is what it is."

"You say that so casually-"

"Because there is no fixing it," Zim says plainly. "Why dwell?"

Dib opened his mouth, closed it, and repeated the action several times. Zim pondered if he was ill before Dib sighed dramatically and flopped back against the tree. "Damn it, that's a good point."

"Of course it is, it was Zim's point," Zim says triumphantly. Dib chuckled. He suddenly sat up, almost knocking Zim off balance.

"Wait! You can learn about the entire evolutionary process using Earth species! There are entire books and documentaries on the theory. Personally, I don't think it should be considered a theory anymore, the evidence to back it is enough to say it's fact, but… the scientific process is what it is. Anyway, I'm rambling now-"

"Yes."

"-but, you can learn everything about evolution and biology that you want from Earth. You'd know more about it than any other Irken!"

Zim hummed. It was a tempting prospect. He sat up, stretching. "Zim will consider it."

Dib knew he was teasing him. He rolled his eyes. "Yeah, sure."

"To answer Dib-stink's question," Zim began, extending a leg for Dib to grab. Dib grasped it at the joint, letting Zim lift him off his branch and into the open air. Zim removed his gloves, storing them in his PAK. He began their descent, using his other three metal limbs for support. "Yes, Irk had an ocean at one point. Irkens used to hunt its lifeforms as well as terrestrial lifeforms."

"Did you use boats, like humans?"

"They could be called that. They were 'fishing' vessels. Many human hunting techniques would be a common occurrence on other planets of highly intelligent civilizations," Zim says.

"You just admitted humans have high intelligence," Dib mocked.

"That being said," Zim growled. "Other life forms evolved to hunt effortlessly without the aid of invention. Irk conquered once such planet early in our history."

"Were Irkens always conquering planets?" Dib asked. "Seems like something that'd hit an end at some point. Haven't you ever thought of what would happen if you ran out of planets? What would you do?"

"Zim… does not know."

Dib waited for more, but Zim wasn't talking. He looked down to see Gir running excitedly in circles. Zim dropped from the tree, lowering the limb with Dib so that he could land himself. He did so with a thump, narrowly missing Gir as he ran by him.

"Well, um…" Dib began awkwardly. Zim gave him a curious glance as he composed his disguise for their walk home. "Well, I think Irkens could do what you're doing now. Just… enjoying living. And learning. On new planets with new species."

"Irkens do not… socialize," Zim explained. "Few planets have treaties so that their colonies are not conquered. They are primarily trade agreements."

"Why do you need trade agreements? Don't you use resources from planets you conquered?"

"Resources are limited," Zim says. Dib regretted the question. He had known that. He could have answered that on a test when he was a child. His face turned red and he turned to begin their walk home. Zim followed, ignoring Dib's embarrassment. "Humans do the same thing. It's economics."

"Heh. Alien economics. That'd probably still be a boring class," Dib muses. He turned back to Zim as he ducked under a branch. "Were there mountains? And streams? And forests?"

"By the time the PAK was initiated, our planet was much like yours. Dwindling resources, areas of land, and untouched expanses. Our native fauna had gone virtually extinct as well. After that, plants were inessential."

"But- don't you have to breathe?" Dib asks incredulously. Zim laughed at him, throwing his head back.

"We do not have to eat for months at a time, nor drink liquids. Breathing was child's play after those adjustments. What few foliage was left was used underground in facilities that pumped the necessary air into the landscape above. If we used it at all," Zim said, remembering the stacks supplying air standing beside the factory smoke stacks. One would have the smoke of industrialization billowing out while the other appeared to emit nothing at all.

"You… your species converted the entire surface? The entire thing? What about those rare patches of land you told me about?" Dib asked.

"Those are on other planets. It is merely rumors if there is but one on Irk," Zim says. He pauses. "But Zim can see the appeal of such rewards. Nature is quite beautiful. If Zim had conquered this dirtball, he would enjoy the outdoors most."

Dib stared at Zim for a moment and then stared down the path. He glanced back at him several times, trying to process the information. "You. Your species. You enjoy nature because you miss it, I'm calling that now. You have memories of every Irken before you that wore a PAK, your species must be having some weird nostalgia for nature. No wonder you calm down so fast when we go to the park."

"It is… peaceful," Zim says. Dib caught the genuine smile cross Zim's face and smiled himself. Zim breathed in deeply, letting out a content sigh. "Relaxing. Irkens do not relax often."

"Now you have a lifetime of relaxation," Dib said. Zim faltered in his walk. He blinked and looked at the forestry around them. He hadn't thought of that.