A/N While I generally like writing and reading according to canon, and exploring things that aren't explained in the series, sometime I like to ask the 'What if' question.
Beta checked by Eddy13.
AU, From the episode 'The Full Monkey'
Kim Possible: A Monkey's Tail
Prologue: Flashes and Fur
"Huh? Wade, I'm pointing, but there's no zapping!" Ron looked down at the Kimmunicator in barely repressed panic.
The genius frowned as he realized that nothing was being channeled through the Kimmunicator. He quickly checked his wires, and realized that he had connected a couple of cables incorrectly. "Sorry, wrong cable connector." He bent down and pick up the correct ones, quickly reconnecting things so the power flowed through the Kimmunicator. He looked at Ron and let him know that everything was set.
Ron stood, lifting the Kimmunicator up, and pointed it at Kim, but he couldn't get a bead, as she performed a number of different moves that kept her away from Monkey Fist. Finally she moved like she was going to jump upwards, over the villain, and Ron realized that he finally had his chance. He raised the Kimmunicator, and pressed the firing button. The beam lanced out into the air...
...but missed completely. As Kim timed her jump, she finally found the one downside to having a tail. Monkey Fist moved forward, and he lifted one of his feet, using it to grip her tail and keep her rooted to the ground. The monkeyed teen let loose a yelp, and almost took a hit as the villain attacked her. After setting herself, Kim was able to block the next few blows, then was able to deliver her own attack, and Monkey Fist went spinning across the ground; at this point, a number of security guards and Mr Barkin came out of the side doors, surrounding and apprehending the monkey man. He was quickly carted off.
Kim turned towards her best friend, and made her way across the gym towards him. She stopped in front, looking at him, then down to the Kimmunicator. Ron never took his eyes off the screen. "Wade, hurry, we have to fire again-there's not much time."
"I know!" Wade was frantically typing, trying to get his systems to recharge faster. "I'm doing all I can, but it takes a while." Another few heartbeats, and then he finally looked up. "Okay, try again."
Ron pressed the button instantly, and a whitish beam fired out, catching Kim in the chest. He was expecting a flash, and then Kim, normal, to be standing in front of him. Instead, there was a slight brightening in the room, as the yellowish white penumbra surrounded her. Her fur seemed to ripple, the colors changing slightly, dimming and brightening, almost like it was trying to combat the change. Ron watched the actions in surprise, unsure of where to focus, on her skin, her fur, or what. Finally, he looked upwards, catching her brilliant green eyes with his. He saw her eyes widen slightly, as she felt herself start to change back, but the relief he saw in her face was short-lived. Soon her eyes darkened, and she reached a hand up towards him; Kim's eyes locked with his, and he knew that he would always remember the sheer terror that he saw there.
And with a brief, bright blue flash, Kim Possible was a monkey forever.