Whelp, here I go again. Yay for new fandoms. \o/

GLaDOS-Miku!Vocaloid is mute-well not really but she hasn't used her voice in so long that she coughs up blood when she tries to talk, ergo, she stays silent- except for when she sings because Vocaloid can sing no matter what or... Something... Uh please bear with me here. Artistic license!

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"This was a triumph! I'm making a note here, huge success..."

Zat growled to herself as she heard GLaDOS's small voice rise from her room. This was about the 875th time the girl had sung her 'first song'- and that wasn't even counting the two days since she'd started. To make matters worse (at least for Zat), she couldn't even complain to her sister, who was absolutely infatuated with the little Aperture pest. Miku would always pester Zatsune to at least try to like the kid, but Zat was nothing if not stubborn, and continued to glare at the younger girl at each passing moment.

So now, the dork wouldn't stop singing, probably relieved that she didn't start bleeding when she did. And now she could be as friggin loud as she wanted!, Zat noted with completely false enthusiasm.

As she stared down at her Xbox controller, she caught herself humming along to the tune. Damn, why did the little chatterbox-or, rather, /music/ box- get the catchy song?

"Now these points of data make a beautiful line! And we're out of beta, we're releasing on time!"

Zat snarled and tried to focus on sniping the Elite onscreen. Though, it was hardly sniping with a rocket launcher. And a bottomless clip.

"So I'm GLaD I got burned! Think of all the things we've learned! For the people who are,-"

Zat already knew what line was coming next, and she swore to god if the ninny didn't stop in two-point-five seconds, she would be anything but-

"Still Alive!"

Oh, that was it. Zat stormed into the younger girl's room- well, really, it was Miku's, because apparently the pest enjoyed sleeping in Miku's room more than her own. And to be honest, the pest in question- GLaDOS -didn't look much different than Zat or Miku- save for the palette swap, the age difference, and the usual silence.

GLaDOS looked up from her keyboard at the clearly infuriated Zatsune. As usual, she decided to pretend not to see the blaringly obvious [from her experience, pointing it out almost always made the person angrier], and instead spun around in her desk chair, momentarily distracted from her game of Minecraft. She pointed a puzzled expression at Zat, who immediately responded with a snarl and a glare.

"Oh you know DAMN well what I'm angry about, robo-girl." she hissed. GLaDOS flinched at the name-calling- she had been created at Aperture Laboratories and, well, she didn't like to be reminded of that... Aperture had at one point attempted to take down Crypton, and was not exactly known for treating its creations well. And trying to fit in with something like that on your back wasn't easy. At all.

She fixed a steady gaze back at the older girl. Some days she really wished she could be as nice as Miku was- or at least just ignore her- but the thought wasn't going to help now. Zat was in full-blown pissy mode, and nothing GLaDOS could do would stop it.

"Look, you've been singing that GODDAMNED song for THREE STRAIGHT DAYS now. I am attempting to beat Halo, so if you could just shut the hell up like you're SO ACCUSTOMED TO?" Zat yelled.

GLaDOS flinched again. "Not... my fault... my vo-vocal *coughcough* chords... don't work... normally..." she strained, swallowing hard.

"Whatever! Just shut up already!" Zat growled.

GLaDOS glared now- she was sick and tired of Zat yelling and yelling and yelling at her! And if her clock was anything to go by, Miku wasn't going to be home from her recording session for another two hours. So she gathered up what little resolve she had by now, and retorted sharply,

"Well, why d-don't you?"

Zat was quite surprised to see the little dork reply so quickly and harshly. She glared harder and snapped back,

"Did you just tell me to shut up?"

GLaDOS had the faintest trace of a smirk on her lips as she replied cheekily, "Sure di~id...", sticking out her tongue slightly.

"Why you little-!" Zat shouted, and lunged for the younger girl. GLaDOS only grinned as the raven-haired teenager began to chase her around the room.

"Y-you can't caaa-*cough*-tch me, you can't *cough* caaatch me," she laughed as Zat tried fruitlessly to grab the child.

"You- little- dork! Get back here!" she yelled as GLaDOS taunted her. Suddenly, she noticed a blanket dangling off of the bed. 'Oh, this is too perfect...' Zat grinned to herself as she quietly tugged the comforter off the bed.

"Okay- fine! You- *pant, pant* win!" she pretended to bend down and catch her breath. GLaDOS, sensing a trick, cautiously edged forward.

"R-really? I *cough* beat you?" she asked, suspicious and a little hopeful.

Zat flashed her trademark 'evil' grin. "Nope." she smirked as she caught the robo-pest up in the blanket as easily as netting a butterfly. GLaDOS yelped as she felt one of the older girl's hands tighten around her wrists. GLaDOS was veritably helpless as she squirmed in her grasp, laid out belly-up on Zat's lap.

"Don't you know what I do to little girls who annoy me?" she laughed as she watched slow realization dawn on the girl in her lap, and as GLaDOS struggled even more. "I did it to my little sister too, when we were younger..." she purred. GLaDOS gulped and attempted to hide her stomach from view, having a bad sense of what was to happen next. Suddenly, Zatsune's free hand flashed out, and her fingers began to scribble at GLaDOS's stomach and ribs. GLaDOS had barely time to react as the sensation caused high peals of laughter to rip free from her throat.

"Z-Zat! S-stoooooppp iiitttt-" she pleaded, her voice broken up by giggles.

"Oh, I don't think so, kid. Now it's time for me to have some fun." Zat smirked, then resumed her ruthless tickling of the younger girl.

Little known by them, they were being watched. Luka- after first hearing the high-pitched squeals- had come up to investigate, wanting to make sure Zat wasn't getting too upset with GLaDOS's singing. She smiled to herself as she walked back down the stairs, reasurred by the scene that Zat wasn't getting too... rough...

Meanwhile, both GLaDOS and Zatsune were tiring. "Alright, you can get up now." she muttered, releasing GLaDOS's hands and making one last swipe across her ribs.

"Th-thank you..." GLaDOS murmured tiredly. They sat in silence for a while, until Zat spoke up.

"Y'know, I don't much feel like playing Halo anymore..." She was startled to find a warm weight against her side seconds after she finished her sentence. She looked down to find GLaDOS half asleep against her. "Aw, really? Look, I'm not..." she trailed off looking at GLaDOS's contented smile as she listened to the thrum of Zat's heart. Zat heaved a heavy sigh. "Fine. Have it your way." She rolled her eyes as she pulled GLaDOS back onto her lap, wherein the girl in question snuggled even tighter to Zatsune. "Mnf. Jeez, even when you're asleep...? Alright, alright. I'll stay..." she yawned as GLaDOS's breathing grew long and deep... And soon Zatsune's did as well.

Miku was understandably surprised when she got home to see Zat and GLaDOS, of all people, curled up on her floor together, but she smiled when Luka told her what had happened.

The next day, Zat was a bit less irritated when GLaDOS began to sing- even (quietly, of course) harmonizing with her own voice...

"This was a triumph! I'm making a note here, huge success!"

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Eeww horrible attempts at fluff. Or something. GAAAH I DUNNO

Anyway. I (as usual) have an entire fic idea revolving around this Vocaloid/Portal thingy. Yay for adorable GLaDOS models.

If you feel it necessary- then yes, do kill me. Before I start something else with abysmal chances of the power of finish. :D