So what's there to say? Another long oneshot for this fandom, using lots of side characters whose names I had to look up. I figured that there's already so much focus on the dark, bleak sides of these characters, so I wanted to do something with another side... an almost altruistic instinct.

Sorry for the long length. Warnings: violence, blood, mild Gretchen/Dib, almost ZADF, and practically pure action

Disclaimer: I don't own Invader Zim

The chalk screeches and breaks, bits of white crumb trailing off the blackboard. ALTRUISM is etched into the dusty board with hate.

"The definition of altruism," Ms. Bitters hisses, "is increasing the fitness of others, in other words the survival rate, at the expense of one's own fitness. A completely pointless behavior, seeing as everyone is doomed to start with."

She glares at the students, ignoring raised hands. "Anyone who attempts altruism is a complete, utter doomed moron."

"Look at him, fidgeting," the little boy mumbles, "all that alien... alienness... ness." Dib narrows his eyes, fists clenching and unclenching over the pencil. Something hits him in the back of the head. He whips around and glares at the eraser's owner.

The girl blows a rasberry. "Typical," he says, "just typical- do you guys even know how much I do for you all? No, of course not!"

"You're weird." "Yeah, weirdo." "Crazy."

"You- oh, why bother." He sinks back in the chair, eyes darting back to the green "boy."

Zim stares out the window, chewing the end of a pencil. He twitches and shifts, speaking under his breath. Dib catches the words "Calculations... no way... lies... they wouldn't come now... why now?... no... no... I am Zim!"

The Irken's eyes widen, artificial pupils dilating. A black dot in the sky. He hopes it's just an Earth bird, a big one, what do they call them? Sea-gals, yes, sea-gals. But he isn't near the sea.

The dot is bigger. The pencil snaps in half- he spits a splinter out.

"What's your problem, Zim?" Zita asks, disgusted at the display. "Silence!"

It could just be a pathetic human satellite. After all, his calculations were precise- he would be ready when they came. He beat them before; there was no reason why he couldn't beat them again.

But now there's no time for preparations. The ground shakes.

The ship is big. Why here? Why now? Why didn't they wait to align with his calculations. WHY? WHY? WHY?

"Be quiet Zim!" the teacher snaps.

"Ms. Bitters, it's another one of his evil plans!" Dib screams.

"No! I'm normal!"

"They're here, aren't they?"

Zim's jaw drops. "You- you! How did you know! This is your fault isn't it?"

"My fault? That your armada's coming?"

"Eh?"

"Why would I want Earth destroyed? That's stupid! I'm trying to save it, remember, you idiot?"

"I knew that!"

"Both of you, shut your pathetic mouths!"

Dib blinks.

The window shatters, glass panes flying forward, and debris exploding. The classroom shakes, the blackboard topples. A light panel crashes. And there's nothing but screaming as a torrent of wind blasts at the children full-force.

An alien ship. He knows it has to be one.

Dib's head hits the wall as the blast throws him back. It hurts and he's tempted to groan. Figures step out, one hulking extraterrestrial and one with a slimmer build. But their looks don't matter to the boy. They're aliens.

And he has a feeling they aren't just lost.

"We're in the right place, right?" the slimmer one asks, checking a monitor in its hands. "Oog-ah? Hello? Oog-ah?"

The large one growls. "What's it say?"

"Oops, my mistake- it should be in the basement, eh, somewhere. Somewhere deep down."

"Mm."

Dib climbs to his feet, right before his ears ring with a sharp noise.

"Nooooooooooooooooo!"

Zim jumps over a smashed desk and scurries over to the new arrivals. "Go away!" He has no better argument. "Go away! Haven't I told you- this planet is off-limits! Off-limits!"

"You look familiar," the slim one says.

"Nik, I don't like him."

"Yeah, neither do I. There's something about you..."

"See!" Dib shouts, "aliens! Now are you convinced? Look- look at him, talking to them!"

"Can't you see that Poonchy's in pain? Don't be so insensitive, man," M snaps. The students are huddled on the floor, Poonchy in the middle, a red gash on his head.

Ms. Bitters sits on her ruined chair. "Finally, we're doomed." She almost sounds relieved.

"Why are you even here!" Zim screams, "tell me!"

"Well, uh, we don't like talking about our plans, but since you asked," Nik says casually, "there's a magnetic core down here. We'll just use it to respond to our receptor, and throw this planet into the sun- it's a lot easier than what we did last time."

"Well, get off! This is my mission- I would have thought you'd learn your lesson last time! You pathetic, horrible, horrible, savage-"

One of the girls screams as Oog-ah throws a fist at the smaller alien. A hard one.

Zim is hurled through a wall, the cement cracking into pieces.

Melvin screams and throws himself out the pane-less window. Dib knows this is bad- throwing Earth into the sun? That would destroy them all! The teacher remains unconcerned. The two aliens walk through the hole in the wall.

The basement- the underground classrooms. That is where they're headed.

Dib dashes after them, his classmates running with him in a frenzy, screeching and crying. The rest of the student body litters the the hall, scampering and clawing their way to the nearest exit.

He goes the opposite direction.

"Lockdown beginning in 10-" the intercom booms.

"Skool lockdown in 9-"

"Hey!" he calls.

The aliens stare blankly at him. "You can't do this," he says, feeling rather tactless.

"7."

"Sure we can," Nik responds with a shrug.

"No you can't!" Dib positions himself, ready for a losing fight.

"4." The skool is skipping numbers.

"Evacuate staff," the announcement says.

"Bighead boy is nosy," Oog-ah comments. He looks down at Dib, reaching for the holster. Nothing. He forgot to bring the weapons. Angry at the mishap, he seethes.

"1."

The Skool is locked, the few students left desperately banging the enclosed doors. Dib dives under Oog-ah's legs and slides away- if he can reach the receptor first, then maybe he can- no, he doesn't have time to think of a plan.

The alien grabs the scruff of his coat and the boy lands a punch in his face. "My nose!"

But he doesn't have time to relish in the victory before he's kicked into a row of lockers, the steel bending with the impact and the structure crashing down. Something pops. And the pain sets in.

His shoulder burns. Dib struggles to sit up, the metallic taste of blood in his mouth and a trickle down his nose.

"Let's get rid of him," Nik says with disgust.

"Yah."

Someone steps in the way, a shaking form with purple braids. "Gretchen?" Dib sputters, "why are you still here!"

"D- don't hurt him," she says meekly to Oog-ah.

It sets in- someone is trying, actually willing, to protect... him? Dib? And for a moment, the boy is unable to speak. Gretchen screams, the alien lifting her up. "Get rid of metalmouth too."

Clutching his shoulder, Dib leaps forward. "No!"

He barely catches the girl, both crashing on the hard ground, his shoulder ache increasing tenfold. That was not the throw Oog-ah expected. He glares at the pair, rubbing the back of his head before turning to look behind him.

A battered textbook had been thrown at his head.

Zim stands, teeth clenched angrily, pink blood trailing from the side of his head and a rapidly growing purple bruise under his eye. "You don't touch the humans, that's my job, mine!"

The Irken stomps one foot for emphasis. Plans? Who needs plans! He is Zim and Zim needs no plans for victory!

"What's going on, spaceboy?" Dib asks, sitting up, Gretchen shaking against him.

"Stupid stink-beast!" Zim growls, "these are the Planet Jackers, and your planet, Dib, is about to be jacked!"

"Wait- that's the name of their species? That's stupid!"

"You're stupid," Nik retorts.

There's another scream, and Dib looks down the hall in horror- most of their classmates are still in the building. "Run!" he yells.

But they don't.

Zim's pak legs burst out and he charges. The legs cut into the walls and scrape the floor and slash the lockers. He dodges and runs and eggs the Planet Jacker on. It isn't long before Oog-ah grabs the legs and rips them apart, the tearing of metal and electricity all too familiar to the little alien's auditory senses.

Zim hits the ceiling and crashes back down, one contact sliding away from reach and the wig slipping off his head. He props himself up stiffly, just as recognition sets in Oog-ah's eyes.

"You!" The little green man. The one who made them lose their loot. Now he's angry.

Had it been any other day, Dib would rant about Zim being an alien, but it's not any other day, and he's never had to deal with saving lives in such close proximity. He feels scared.

"Come on," he tells Gretchen, taking her by the hand and leading her toward their classmates.

"Happy now, Dib?" Jessica says, "now we're all gonna die because of some stupid aliens!"

"Aren't you supposed to be saving us or something?" Zita adds.

"Guys, he doesn't owe us anything," Bryant says from his spot in the corner, hugging his own knees. He looks almost apologetically at Dib.

"I don't do something just because I owe it," Dib states coldly. But he is going to save his classmates, somehow.

Gaz. He worries- where is Gaz? He hopes she evacuated.

"The receptor's that way," Nik says, pointing at the group. Aki screams.

"Aliens blocking our way," Oog-ah barks, "so annoying." One hand holding Zim by the antennae, he marches toward the students, ignoring the Irken's cries of pain.

"Now would be a good time to move!" Dib snaps.

But again, they're frozen by fear. "You're kidding me," he sighs.

Zim wriggles loose and crawls onto Oog-ah's shoulders, preparing to dig one claw into the alien's eye. Nik yanks his leg, and he's slammed on the ground. Dib tackles the other Planet Jacker with enough force to send them both to the floor.

"Gretchen, take everyone and run!"

The girl nods and pulls at Bryant. One by one, they snap out of the daze and take off, Torque zipping by Nik.

Zim attempts to sit up, only to be pounded down again. And again. And again. Oog-ah picks him up and there's a moment of silence. Dib rolls away in pain, his shoulder jolted.

Crruuuunncchhhhhhhhhhhhhhhhh hh.

"And stay down," Oog-ah spits.

It hurts a lot. That is all the Irken can think of. He can't tell what hurts, but he knows it isn't something that would heal in a few days. He gasps sharply, fractured bones rubbing against one another with each movement.

"Where's the tracker?" Nick asks, panicking.

He kicks Dib on his side and inspects the boy. Who would be daring enough to- that Earth boy, the bigger one. "Oog-ah! Someone took our tracker! One of the aliens did it!"

Without a word, the other alien stomps down the hall, Nik trailing behind, both letting out a string of odd curses.

Dib sits up, he has to follow- what if blood is shed again, and it's not his own? He looks down at the Irken, Zim's body bent at unnatural angles.

"Zim, I need your help."

"D- don't you always need... my amazing..."

"I know I know! Save it, Zim. We have to stop them- now."

The alien stands up, littered with nasty bruises and leans on a wall, breaths coming out heavily. "The basement- go, dest.. ah... destroy the receptor."

"What does it look like?"

"I don't know! Figure it out... stink- ugh, beast!"

"Can't you do that? I have to save some jerks."

Zim sucks in another painful breath- why is the Dib so disagreeable? "Zim shall do that. You go to the basement."

Dib stares at him in disbelief. First Gretchen tries to shield him, now Zim wants to save humans?

"I'll distract them." That makes more sense. But Dib feels a sense of, no, never sympathy for the enemy. Never.

"I'll do it."

"No, I will! My advanced body is obviously- ah- superior to your... pitiful hyooman skin!" Zim snaps. "They'd destroy you in seconds!"

The boy sucks at his split lip. The two glare at one another for one long moment. "Fine; you better not let anyone die, Zim."

"Whatever." "I'm serious!" "Stop wasting time!"

Another heated glare. Dib grits his teeth and sprints away, kicking at the walls and stomping on the ground. There has to be a way into the basement- he's tried before, but the little stairwell in the closet leads to nothing. One of the tiles gives way.

Dib pulls it back, muscles churning and fingernails digging so hard that blood runs down his fingers. He wishes his shoulder would fall off- the pain is almost enough to slow him down. Almost.

Staring into the black abyss of circuits and neon, Dib waits for a rat to crawl away. He jumps in, skidding against the rubbly underground walls until he hits solid ground. He follows a trail of dim blue light, an arrow toward the underground classrooms; there's no better alternative.

Above ground, Zim curses the pig smellies. Why would someone be stupid enough to tamper with superior forces? (Although none were as superior as himself, of course). He limps at the fastest speed he can go, pushing himself off walls for leverage and ignoring the need to gasp.

He sees a shadow at the end of the next corridor, the aliens hunched over the cowering children. Torque and Chunk are glaring back, fists raised. It's pathetic! The tracker is in the Sara human's hands. Even more pathetic!

"Hey!" he shouts, demanding attention. Oog-ah turns. "Over here! I'm not finished with you yet."

"I'm getting really sick of you," Nik moans.

The classmates don't seem to care that Dib was right, that Zim was an alien. They don't have time for it to settle in yet. They scatter again and try to run away, in a neverending circle around the skool.

Oog-ah isn't distracted. He goes in pursuit. Zim throws himself on the alien's back, resisting the urge to vomit. With a growl, Oog-ah slams him into a locker, but the Irken stays on.

Slam. Slam. Slam. Zim sees stars and one grip almost loosens. Almost. He slides down and delivers a kick at Oog-ah's jaw before latching onto the chest and throwing small punches. Physical combat is the most savage of practices and any Irken knows this- it's almost embarrassing.

"Zim!" Aki's shrill voice calls. His antennae perk. "It is you..." he hears her murmur.

It's obviously the human's fault that in the next second, he's on the floor, practically wedged into it, pieces of concrete tearing at his skin.

"It's got Sara!" She yells between hyperventilating sobs.

Oog-ah is gone. Zim crawls out of the hole, shreds of uniform falling to the ground. He wants to ask her how is that his problem. But instead he says, "I'm normal... and human."

She has hearing problems, he bets, because then she's thrown herself on him, arms wrapped around his shoulders so tightly that he wants to scream. Why does everything hurt so much? "Please, you have to save her!"

She pulls apart from him, hands covered in sticky pink fluid. His blood. The pain clears ever so slightly and he remembers that Sara has the tracker. Foolish stink beast. "Zim will," he rasps.

It's hard to move but he manages to do a semi-run, hugging the walls and lockers, Aki leading him on. They end up stumbling into the girl's bathroom, the students' screaming echoing off the white walls. Nik stands before a stall, plunging Sara's head into a toilet.

"Where is it?" he demands. "Where?"

"Ahhh!"

Dunk. She gurgles.

"Where?"

"Ahh!"

Dunk. Gurgle. Zita kicks him in the leg. "Leave her alone!" Zim chuckles; stupid humans. It's kind of funny- maybe he'd just watch a little bit longer...

"Zim!" Aki shouts again. "Do something already!"

Oog-ah grabs Sara when Nik turns his attention toward the other girl. And now Zita is screaming as he carries her toward the sink. Bryant cowers under it, Torque and Chunk trying to do something with the trash bin.

Zim throws a wad of paper towels at Oog-ah. The Planet Jacker looks down and glowers. "Still not dead?"

Sara falls to the ground unceremoniously. "Of course not," the Irken says. He cracks a grin, one swollen eye twitching. Nik shoves Zita in the sink, but she wriggles free. Zim puts one leg in front of the other, painful grin still plastered. The Dib must be slow- the tracker is still beeping- he can hear it. The receptor isn't destroyed yet.

He considers calling Gir. But the Planet Jackers are brutal and he doesn't want the SIR harmed. He must have been in more pain than he let on- where did that come from! No, he doesn't call Gir because the robot will just mess things up as he always does. Yes, that's why.

"Kill them Zim!" Bryant screeches, spazzing. Now they're all behind him, crouched on the floor, expecting their alien to come out on top.

Below, Dib fights off an horde of rats. One sinks its teeth into his arm- with a yelp, the boy shakes it off. There are no students- he wonders if only his classmates were stupid enough to get locked in. It is very possible.

He rounds a circular hall, the sickening lights nearly messing up his vision. But he's made it and the receptor is staring at him, a gigantic mass of metal and churning machines. The words Knowledge is Power, Ignorance is Bliss run in circles around it. Dib steps toward it.

Zap. He falls down, an electric current passing through his body. Security mechanisms.

He charges toward the forcefield, screaming against the pain that follows as he tries to force his way through. He's stuck in that position, nerves frying and clothes singing. He can smell the burning of skin.

INTRUDER ALERT the mechasims blare. There are explosions all around him, incinerations. Dib falls back and something booms under him. Then another. He groans, little drops of blood on the ground and blackened skin showing through ripped clothing.

He braces himself- the explosions follow his movements. If he can lead it into the forcefield, he can get through-

Above, Zim's body breaks down the bathroom door. He stands up shakily as Oog-ah's fist cracks against his skull. The Planet Jacker throws him into another wall. He doesn't have the chance to stand this time.

Oog-ah pulls a light panel from the ceiling and shatters it over the Irken's body. Zim cries out as his skin burns and the glass digs and slices. The larger alien grows impatient, pressing down against the large shard wedged in the invader's side. It's enough for Zim to taste something in the back of his mouth- it's not saliva and it's not bile.

Oog-ah stands up as the small alien coughs up blood, feeling his squeedly spooch rip and jolt. Zim crawls out of the glass, bleeding green claws showing through ripped gloves.

"What's taking you so long?" Nik asks, tapping his foot. He still doesn't have the tracker.

The children are backed against a singed wall, holding one another, trying to hide the tracker. By instinct, they know that it is bad. That there are all kinds of "bad" in the world and that the tracker is one of the worst.

"Where's Dib?" Gretchen asks. No one answers.

Below, there's another explosion and Dib is on the other side, dizzy and burnt. He crawls toward the machine, spying a small opening on its large side. The boy shoves himself in.

He crawls down the narrow chute, biting his tongue to the point that it draws blood. He makes it to the wires. There is one thing he knows about destruction- randomness causes all forms.

He puts one in his mouth and bites. He tears the wires apart one by one, teeth going numb and gums bleeding. He breaks the last one with his ruined nails and he hears a boom.

Dib flies into the air and slams against the hard ground as the explosion passes. His body screams at him and he tells it to shut up.

Above, Oog-ah puts one foot on the Irken, the alien's body practically covered. He crunches down. The ground cracks.

Zim's eyes are shut tight. He can feel the internal beeping of the pak- it's not a good sign. He tries to pull himself up, tries to force broken bones to move, tries to keep his bleeding spooch from hurting. He makes it, one hand pressing tightly on his side.

From his blurring vision, he sees the tracker change hands. The humans are standing at least a foot apart from that one girl- Zita now.

And that is why Oog-ah isn't still crushing him. The Planet Jacker is staring down at the girl. Zita clutches the tracker, knuckles turning white- her legs shake. Throw Earth into the sun: for some reason, she remembers this. She doesn't want to burn- she doesn't want anyone to burn, not even her most hated classmates. She braces herself for a blow.

"The definition of altruism," Ms. Bitters hisses, "is increasing the fitness of others, in other words the survival rate, at the expense of one's own fitness."

But Zim is in front of her by then, a sloppy trail of pink gushing down his form. The punch gets him in the jaw.

The beeping stops. "The Dib."

The Planet Jackers exchange looks, confused. If the receptor stops, then they failed. How? They freeze. Zim chuckles to himself, the Dib has succeeded.

"You," Oog-ah almost hisses, veins popping.

He grabs the Irken by the shoulders, furious, the latter too drained to protest. Crraaaaaaaaaaaaaaaaaaccccccc cccccccccckkkkkkkkkkkkk.

There's another sickening crunch. Oog-ah drops him, hands stained with fresh blood. He moves in for another blow. Something cracks on his skull.

Dib stands behind him, looking worse for wear, and holding the handle of a mop. "Hey, didn't you hear him?" the boy wheezes.

"This planet is off-limits."

"Dib!" Gretchen cries. "Dib!" Bryant cries. For once, his classmates are happy to see him. But Dib doesn't care about any of that.

Oog-ah lifts him by the leg and Dib screams out his plan- a spontaneous burst of good luck that he discovered underground. "Zim!" he shrieks, "the skool code's 78190XJ! Use your pak!"

No one has any idea what that means. Dib's head collides with a wall and he slides down.

Zim hears it- he understands his enemy- always has and always will. He knows what Dib wants. The pak charges itself, one wire extending and claws sprouting into a nearby wall. The data runs through his system.

Dib gets up shakily. "This place is going to blow up!" his hoarse voice screams. "You two aren't leaving!"

The aliens exchange glances. Their eyes widen and they roar. Annoyance and frustration and everything in between.

"What about us, Dib!" Jessica asks.

There's an unlocked exit in one of the hidden passages- a system he only recently discovered while coming back up. Dib keeps his mouth shut; he can't let the Planet Jackers know.

"I don't know- just come with me!" But he winks awkwardly at Gretchen.

Torque shoves her aside and is practically stuck to Dib's back. This is how much they trust him now. The skool blares red.

"Zim!" he calls, "leave it!"

The code is done. The pak detaches from the wall and Zim hobbles toward him, the other aliens following suit. Except the Irken doesn't follow Dib.

"Go!" He stays between them and the Planet Jackers. "Just go, Dib! Save your unworthy piles of meat!"

And in that moment, something clicks between them. What they're doing makes sense, it's the same reason why Dib tries so hard to save a race that hates him, why he risks neck and limb for mockery and nothing. It's why any Irken would do anything for their Tallest. It's why Zim doesn't call Gir. It's why Zim goes on the field and leaves the robot behind.

He throws himself at Oog-ah's torso, sending them both slamming into Nik. Dib goes away.

The sirens stop and everything goes boom.

...

...

...

"Zim."

Everything hurts.

"Spaceboy."

He's numb and tired and somewhere between burning and horribly cold.

"Zim, you alive?" The voice is desperate.

And annoying.

Zim's one good eye opens. Barely. Dib is leaning over him, nothing but blackened ruins all around them. The Planet Jackers are charred and unconscious beside them.

All that body mass must have saved him. Dib blinks through cracked lenses, assessing the Irken's battered, torn form. The blood pools around them.

"Thanks," the boy says softly. "I guess."

"They know now, don't they?" Zim manages to cough out- that is his only concern- if they can access his pak, if they can see the Irken race- no, he couldn't allow his empire's secrets to be-

"They won't tell. At least, not now." Then more quietly. "I won't let them."

Even more quietly from the Irken. "Zim thanks you."

They almost smile. But everything goes dark and Zim feels so, so good.

And Ms. Bitters is A-Okay. I think I'll keep this as a one-shot with an open-ending. Thanks for reading and feel free to review!

I had a really good time writing this and I hope you had a good time reading this. So why does the skool have this magnetic core? Because it's Skool and it's controlled by a corrupt government so it's only logical that the first signal the aliens pick up is the skool's internal system database, right?