What if Shego's comet powers were more powerful than we originally thought? What if her true capabilities were simply waiting for her 25th birthday? Kigo

Disclaimer: I do not own Kim Possible or Shego; if I did I would never have cancelled it. Also, there would be kigo

Beep beep be-beep!

Kim Possible- high school teenager and world renowned hero- looked up from the ridiculously large amount of homework on the desk in her room and switched on the small beeping device.

"What's the sitch, Wade?" she asked with an almost-too-cheerful tone. The boy in the screen of her kimmunicator gave her a knowing look.

"Let me guess, doing homework?" The 10 year old genius eyed the mountain of paper behind her. An exasperated sigh and a nod confirmed his suspicions. "In that case, good news. Drakken and Shego have stolen a huge generator from a lab not too far from Middleton. Thankfully, the scientists put a tracer on it and I was able to track them to a mountain in the Arctic Circle. Your ride will meet you at the Middleton airport in 30 minutes."

"Did you call Ron?"

"He's already there."

"Thanks Wade, I'm on my way." With this, Kim hung up and started pulling on her mission gear, a huge grin on her face. After hours of algebra a good fight with Shego was just what she needed to work out her frustration. She would never admit it to the green-skinned villainess, but Kim really enjoyed their fights and the banter that came with them.

Shego glanced at the clock on the wall of Drakken's latest lair ('lair' was a generous term; it was merely a cave on the side of a mountain). 6pm. Only another few minutes until she hit 25. Her idiot brothers had already sent her a happy birthday email, mercifully deciding not to make a huge fuss like they usually do. It was just as well too, or Drakken would have found out her birthday was today and insisted on a celebration. She shuddered slightly at the thought.

"SHEGO!" Speak of the dumbass… "KIM POSSIBLE IS HEADING UP THE MOUNTAIN!" The mad scientist was a blue blur, making last minute adjustments to his machine. If Shego remembered correctly, it was some sort of massive heater that he would use to melt the ice caps and flood the world. It was frustrating to have to listen to Drakken rant about EVERY SINGLE PLAN HE MADE.

"Relax, Dr D. As usual, I got it." The raven-haired woman made to stand up when a wave of dizziness suddenly washed over her. Whoa… Shego shook her head to clear the fog and walked over to the entrance to the lair. Can't afford to faint now, no way am I missing out on a fight with Kimmie. She smirked at the sight of red hair peaking over the cliff ledge.

Kim pulled herself up onto the ledge, silent and graceful as a ninja. A panting Ron flopped loudly onto the ground beside her. It didn't take long for Drakken to make his presence known.

"You are too late, Kim Possible and….. Buffoon…"

"It's RON! Ron Stoppable! How is that hard to remember?" The blonde boy yelled futilely. It was unlikely Drakken would ever get his name right. "And I'm not a buffoon…"

Kim was paying no attention to this exchange, instead scanning the area for her true opponent. Said opponent was currently crouched on top of a pile of crates to the left of the cave entrance. Soundlessly Shego dropped to the floor and sidled up behind the unsuspecting redhead.

"Hi Kimmie" Kim heard a voice purr in her ear. I WILL figure out how she keeps sneaking up on me, even if it kills me! Instinctively she whirled around and thrust out a fist, which was quickly caught in a black gloved hand. Shego immediately noted the light blush on the younger girl's face. She found it oddly pleasing that she had that effect on her Princess. MY Princess? Where did THAT come from?

The girl in question was inwardly berating herself, feeling her blush intensify at the feeling of her hand in Shego's own. BAD KIM! You are not attracted to Shego! Even if her breath felt so good on my neck… NO! Shaking away such confusing thoughts, Kim swung out her leg to trip Shego up.

Shego ended her own internal debate just in time to jump over Kim's leg and counter with a blow to the gut. Kim grunted and gave Shego a roundhouse kick to her side, knocking her briefly onto the floor. Shego quickly leapt back to her feet and her hands surrounded themselves with glowing green energy.

That's odd, Kim thought. The fight's barely begun, why would she bring out the plasma so early?

In truth Shego was just as surprised as Kim was. It was as if she suddenly had too much energy and it was starting to leak out. What's more, her earlier headache had returned. Still, she shrugged it off, turned down the heat of her plasma (she was fine trading blows, but she didn't really want to hurt Kimmie) and resumed the fight.

About 2 minutes later Kim finally asked the question nagging at the back of her mind. "Are you ok Shego?" She had noticed the thief's moves were more sluggish than normal and her hands were occasionally flaring up only to die down again seconds later.

"I'm… I'm fine…" Shego murmured out through the pain in her head. It felt like the mother of all hangovers plus being hit with a bus. She could barely control her plasma anymore. Unfortunately the level of concentration needed to hold back her power and answer Kim caused her legs to give out from beneath her. She expected to hit the ground hard, but instead found herself caught by a cool (to her anyway) pair of arms and gently lowered to the floor.

Kim was getting increasingly worried about Shego, the villainess was shaking violently, letting out a whimper every now and then and heat was rolling off her in waves. One arm around Shego's shoulders, Kim used her free hand to pull her kimmunicator out of her pocket and speed dial Wade.

"What's up, Kim?" The boy sat, as always, at his computer, ready to help Kim out.

"Wade, can you scan Shego for me? Something's wrong with her and I don't know what."

"Alright, point the kimmunicator at her." Wade was somewhat confused as to why they were helping the bad guy, but the desperate look in Kim's eyes told him not to argue. The data from Shego's scan popped up on his computer screen and his eyes bugged out of his head.

Kim did not like that look on his face. "What is it?"

"Shego's cells seem to be mutating. Her internal organs, her bone structure… they're all shifting. That's why she's giving off so much heat; her body is using a lot of energy doing this." A groan from Shego stopped him from elaborating.

"K-Kimmie… get back… you'll get burnt…"

"Shego?"

"NOW!" Kim complied and as soon as she was at least 3 metres away Shego stopped trying to contain herself.

Kim's eyed widened at the sight of Shego screaming and surrounding herself with green flame. Even Ron and Drakken stopped their slap-fight to gawk, Rufus sticking his head out of Ron's pocket. Black claws broke through her gloves and boots as slender black horns grew out of her head. Two huge blood-smeared wings burst from her back, spikes on their tips. Her face lengthened into a snout and her screams turned into roars which showed off her deadly sharp teeth. A tail tore through her catsuit as well. Shego soon began to grow, shredding what remained of her uniform to reveal emerald green scales, until she was roughly the size of a very large horse.

As the green glow dissipated and the roaring ceased, Kim found herself unable to speak or do anything but stare. For where Shego once stood, there now stood a dragon.

Hello fellow kigo fans! This is my first fanfic, so please let me know if you like it or not. If you have any suggestions, tell me :)