AN: This story will eventually include characters from Avatar, Kim Possible, X Men Evolution, American Dragon and Ubos, Ultimate Book of Spells (which is like a cartoon version of Harry Potter for those who don't know it).

Disclaimer: Clearly, I don't own any of these shows. If I did, this would be a cartoon on TV, not a fanfic

Rise of the Cosmic Creature

Aang yawned widely as he flopped onto the bed of sheep wool, snuggling into it as his eyelids closed. Being awake so long and being so overstressed had done a number on him. he'd almost gone insane, though he knew it even as it was happening. Fortunately, his friends, his family, had manage to calm his worries. They were confident that he could defeat the Fire Lord tomorrow during the eclipse. There wasn't a single doubt in any of their minds, despite how sceptic Sokka tended to be. If they believed that much in him, despite all they'd seen, then he had nothing to fear.

Katara couldn't help the warm, loving smile crossing her face as she watched Aang finally fall into a peaceful sleep. He'd been a wreck, if he hadn't finally gone to sleep, he would have completely fallen apart. She couldn't bear seeing him upset or disappointed, so his behaviour had definitely trouble her. Like Toph and Sokka, she found it a great relief that he'd finally let go of his fears as they too settled down for what would be their greatest battle yet the next day.

...

However, fate refused to be kind. For halfway through the night, Aang's dreams changed again. He was enjoying watching himself defeating a pant less Fire Lord when suddenly the whole fantasy started to fade.

"Huh? What's going on?" He cried as all that remained disappeared. Looking around, he found himself suddenly floating in a dull sky, clouds scattered around the area, but no ground in sight. "Strange. This is like the times that.."

"I brought you within your mind to converse." A soft, wise voice ended for him, drawing his attention upward. A small grin crossed his lips as the glowing dragon spirit of Fang descended towards him. However, it turned into a frown as the dragon's descent brought him face to face with grave looking elderly man in a very formal robe: Avatar Roku.

"Roku! It hasn't been that long since we last spoke. But you look far more worried this time around." Aang commented, taking a deep breath to calm his suddenly rising nerves. Roku had looked sad before, but he was genuinely confident that Aang could handle whatever was going on. Not sure he wanted to know what was going on, he continued anyway, though clearly hesitantly. "What's going on?"

"Aang, I fear that I must tell you that the Fire Lord has become an insignificance." Roku started, earning a loud, disbelieving gasp from Aang.

"WHAT?" Aang interrupted, his panic and disbelief growing quickly. It wasn't possible that Roku actually meant that! The Fire Lord was the cause of the entire war. Taking him down was the only way to end it. "I can't believe this. What could possibly make the Fire Lord a mere insignificance?"

"A creature that has not been seen in our world for millennia." Roku answered solemnly, shutting his eyes before opening them to reveal something that scared Aang to the core. Deep fear. "Long ago, before the beginning of the Avatar cycle, or even the first human elemental benders, a creature of unimaginable cosmic power descended upon the planet, destroying everything it came across. Nothing, not even the strongest spirits could stop it. The elements meant nothing to it; no one could find its weakness. It reduced half the world to rubble before one day it just disappeared and never returned, with no one knowing why. Those who were left rebuilt and restored their homes and the world eventually, though slowly, recovered and forgot it ever happened. But now, the ancient spirits have felt its power re-emerging into the world. When it does, the Fire Lord will be at its non-existent mercy, just as you and everyone else will be."

"No way." Aang muttered, hyperventilating. He just couldn't believe it. A creature with the power to destroy everything in its path? Dragons, flying bison, badger moles, they'd all been around and even they didn't stand a chance. It was impossible! And yet...despite what Aang told himself, despite what he wanted to believe, he knew Roku was right. And if this was coming back... "So what do I do Roku? How do I stop this?" He asked hesitantly, visibly shaking with fear.

"I'm afraid Aang, that even you don't have the power to stop it." Roku said sadly, shaking his head, resulting in a loud gasp as Aang's eyes widened larger than ever before. "This creature is made of cosmic flames. Despite it being a type of fire, no fire bender can manipulate it even slightly and even if you could, you cannot harm it with fire. It exists quite sustainably even under the sea, meaning water is also useless. It's body is pure cosmic power, so there are no body parts to wound. Simply put it is invincible. No one ever discovered even the slightest of weaknesses."

"Then what do I do?" Aang cried, exasperation, anxiety and fear all mixing in his voice as it grew louder. "Crawl into a hole and hope for it to blow over and disappear again? I can't do that Roku! Countless innocent people will die! They don't deserve that, and I've failed them too many times already. I have to do something to save them."

"No Aang." Roku sighed, watching on sadly as he watched the boy fall into desperation and despair. "Save those nearest to you, take them with you, but you must avoid this creature. If the creature does disappear before everything is gone again, the Avatar will be needed more than ever to restore balance. If you die, you will not be here when the world could truly use your powers. Plus, with what is about to occur, it may very well break the Avatar's cycle if you do die and the world will fall completely. No Aang. Save your friends, both those with you and those coming. Take them into hiding quickly, for the Phoenix shall rise today." With that, Roku's body faded away.

"Roku? ROKU! Wait, come back!" Aang cried, throwing his hand out towards his past life. However, instead of grabbing hold of the former Avatar's robe, he found himself sitting up and grasping at the cool, morning air.

"Aang, what's going on?" Toph groaned groggily, rubbing her head as she sat up. Aang turned sheepish as he realised that he woke everyone up again, Katara already on her feet and Sokka sitting up, looking at him with wide eyes.

"Sorry guys." He sighed, lowering his arm before wiping away the eye crust irritating his eyes.

"Don't tell me you're still having nightmares." Katara exclaimed, not sure if the urge to face palm herself or comfort him was the stronger one.

"At least he made through to the morning this time." Sokka mumbled between yawns. "That got rid of the shadows under his eyes."

"No, it wasn't a nightmare guys. Though, I really wish it was." Aang muttered, curling into a ball as his friends moved closer to him, even Sokka suddenly very worried at that statement. "I was having a good and funny dream, but then Roku came to me again."

"So? He usually gives you good advice and helps you continue on your journey doesn't he?" Toph asked, clearly confused by his mood. "What did he say?"

"To forget the invasion plan and find a hole in the ground to hide away in. That today a power will appear that end the Fire Lord and everyone and everything else along with him." Aang muttered moodily. Still curled up, he never saw his friends freeze in their tracks.

"What? That's crazy! What do you mean everything will be ended?" Sokka cried, his eyes wide and his face paling as he panicked, throwing his arms around wildly.

"He called it the Phoenix." Aang answered shakily, finally looking up to reveal his tears. "A creature made of cosmic flames that's immune to every element that attacked in ancient times." Taking a deep, calming breath, he told them everything Roku had told him. Needless to say, all of them had turned as white as a sheet by the time he had finished. As he got to the end, Sokka turned his eyes skyward for a moment...before they rolled back into his head and he fell back in a dead faint.

"You know, strangely enough, I envy his condition." Toph muttered, falling onto the ground herself. "Then at least I could escape this for a while. A creature that outmatches even the Avatar State in power with no invulnerabilities? How do we survive a fight with something like that?"

"Simple, we don't." Aang answered sourly, clenching his fists. "Our only chance of survival is to go deep underground and hope the Phoenix disappears again. It's that or die."

"Then that's what we'll do." Katara said firmly, forcing her fear down as the other two turned to her. "We'll wait for the invasion fleet and take it and all of the food and water supplies we can through an underground tunnel we'll have the earth benders create and seal. We'll leave just enough holes leading to the surface to ensure we don't suffocate, and create enough turns to ensure that no cosmic fire reaches us. Toph, you'll have to start making it now and have the others help you when they get here. Aang and I'll go gather as much drinking water as we can. When we get him to wake up, Sokka can scour the island for edible plants and animals."

"Well then, we better wake him up." Toph stated, trying, and failing, to sound like her usual smart aleck self as she stomped her foot and shook the ground around Sokka. It took a few moments, but the constant pounding to his back and head got him groaning and opening his eyes soon enough.

"Man, I had the craziest dream. Aang told us we were all gonna die at the hands of an oversized, fiery pigeon." Sokka chuckled, flinching as pain shot up his back when he sat up. "Argh, damn Toph, why did you have to do that?"

"Because that wasn't a dream, apparently we're just gonna run and hide twenty or so feet below the surface and we need you to gather up food for a lot of people for a long amount of time." Toph answered shortly, ignoring when Sokka's eye bugged out.

"WHAT? It was REAL? And we're doing WHAT?" He shouted, turning from one of his friends and sister to the next pleadingly, as if begging them to tell him it was only a rather cruel joke. However, their hard, scared and miserable expressions didn't change. "You guys can't be serious!"

"But we are. Now go and start gathering food." Katara snapped, pointing towards the trees as her fear and panic turned to irritation. "I'll send people over to help you when the fleet gets here. Now hurry up, we have no idea when or where this creature is going to surface. It could be right over our heads in two seconds for all we know."

Not sure whether he'd rather take on the rage of a legendary fire bird or his panicking sister, Sokka quickly jumped to his feet and ran, screaming for the sheep to come back. That was only gonna make them run further away, but the others just shrugged and left him to it, heading off for their own jobs.

...

It was definitely harder getting the message across to the invasion fleet as they arrived. They all trusted Aang and the others of course and some, such as Sokka and Katara's father and a few of his men and their favourite, crazy inventor, accepted it immediately after getting over the shock, but others like the swamp people and The Boulder seemed sceptical. Few understood just how the individual Avatars stuck around after their death, seeing as they were all the one soul, and doubted it was more than a dream. It took a long argument to get them to go with it and it didn't end until Roku took over Aang's body for a moment and talked to them himself before they finally accepted it and helped prepare. Fortunately, the fleet had a lot of supplies left, as well as empty barrels and containers to store more water and food. Sokka was particularly thrilled to see the tanks and quickly had the earth benders widen the tunnel they were making to fit them through, intending to use them for the extra protection should something go wrong.

Everything was going well, especially when Mechanist revealed that he'd created an invention that produced light similar enough to the sun to grow vegetables underground. The barrels were all filled and moved carefully down the weaving tunnel, along with all the supplies they could gather, such as fire wood and blankets. It looked like they would be done in time.

However, that changed right as the eclipse started. Aang, Katara and The Duke were gathering a few things that were left behind in the rush, like a few weapons, plates and the like, when the sky darkened. At first it was reassuring. If any firebenders were to find them right now, they'd have no power and easily handled. But just as they got back on deck, an extremely loud, piercing screech that could have only come from a huge bird filled the air. Plates shattered and knick knacks clattered across the deck as the three screamed in pain, their hands flying to their ears in an attempt to dull the sound.

"What was that?" Duke asked nervously, whipping his head left to right to try and find the source.

"It's coming." Aang whispered, his face filled with pure terror as he turned to Katara, her face paling lighter than Aang's. A moment later, all three gasped and screamed as they saw a red flare moving at much higher speed than even a dragon was capable of moving, right towards them. A few seconds later, the distance had decreased so much that the flare could be clearly made out as bird shaped fire. "It's coming here! Go, RUN!" Aang screamed. Throwing up his hands, he created a strong gust of wind and blew his companions to the sure.

"Aang, what are you-"

"Katara, GO!" Aang interrupted, turning desperate eyes to her as the Phoenix closed in. There was no time for them to reach the hole. However, if he could keep it distracted for just a few moments, maybe his friends would still make it and survive. "I'll hold it off, just get The Duke to the tunnel NOW!"

Tears poured freely out of her eyes as she realised just what Aang was planning. But there was nothing she could do. If they all stayed, they'd all die. If they all ran, they'd all die. Aang was the one person on the planet who might be able to hold the Phoenix off long enough for the others to get away. Choking back a sob, Katara jumped to her feet and grabbed Duke before running off, summoning a stream of water to ride on to move faster a second later. The only chance Aang has to survive is if we get there fast enough and the he can cause the bird a distraction. She thought, desperately hoping it worked out that way as she glanced back. Come on Aang.

Taking a deep breath and suppressing his fear, Aang made his body tense and firm before stomping his foot and thrusting his arms up and forward, sending two giant boulders from the ground at the Phoenix' wings. The boulders collided soundly and as they did, Aang couldn't believe his luck. The bird had actually stopped its progress, its head staring down at him. Though it clearly wasn't hurt. Aang got the feeling from the way it lowered its head to him that it was a little surprised that anything would dare to attack it. It did the job though; Katara and Duke had already made it to the tunnel.

However, all good things must come to an end and the Phoenix was quite happy to make it happen. Releasing a war cry, the bird thrust its fiery talon down at Aang. Thinking quick, Aang leapt as high as he could into the air, only for the Phoenix to swing its wing right at him. Eyes widening fearfully, he screamed as he thrust his hands out and created an air blast, flinging himself back. However, though he evaded the actual wing, he was caught off guard and defenceless as fire feathers the size of the average fire blast detached and shot right at him, landing right on his shoulder and hip.

"ARGH!" Screaming and unable to focus, he plummeted back towards the ground fast. Not about to let him go, the Phoenix dived right after him.

"NO!" Katara and Sokka screamed, watching in pure terror beside Toph as they watched from the tunnel entrance. It was only the fact that even their combined power was absolutely useless against the Phoenix and their quickly growing, intense fear that stopped them from running out to save Aang. At this point, they weren't sure what felt worse: the knowledge that Aang was going to die or the fact that if they tried anything they'd do nothing but join him in his fate. As Aang closed in on the ground, the Phoenix closing in on him, Katara couldn't take it anymore and flung herself into her brother, crying hysterically into his chest as he wrapped his arms around her, but kept his crying eyes on the boy that had become like a little brother to him, refusing to look away. It would be disrespectful to look away as Aang sacrificed himself so honourably.

His eyes closed, Aang had no clue how far he was from the ground or how close the Phoenix had gotten. He had heard his friends' screams and hoped that they'd get away before the Phoenix noticed them. He hoped his death would be quick and as painless as possible. But mostly he hoped that the world would recover, even without him there to help it.

I just wish I could save this world before I go. He thought sadly as his whole body heated up, suggesting that the Phoenix was close. Letting out a defeated sigh, he accepted his fate right as he hit the ground.

However, at that moment, his back collided with a lumpy stone, causing Aang to jerk and arch painfully as a blunt chunk pushed forcefully into his back, right on the scar left from Azula's lightning bolt. Sucking in a deep breath, he was overcome by amazement as a power surged right through him, a power he immediately identified as the cosmic energy of the Avatar State. His eyes and tattoos bursting to light, the energy gathered and exploded around him, surrounding him in a orb of white light just as the two story fire bird collided with him. Katara, Sokka and Toph screamed as they watched on, the flames of the bird all crashing into the earth, sure that Aang was gone. However, the Phoenix released what sounded like a surprised screech as the white orb grew, becoming visible within the flames. For a moment, the shadowed form of Aang could be seen within the orb, amazing the water tribe siblings, before the flames started wrapping around it. A second later, the white ball exploded, forcing the siblings to protect their eyes from the blinding light as the Phoenix gave out one last screech. Then, as quick as it came, it was all gone. Rubbing their eyes, trying to get rid of the white blotches, they looked up to find nothing. No Phoenix. No Aang. No burnt earth strangely enough. It was as if the two beings had never been there at all.

"What? What happened? Where did they go?" Sokka asked, looking around wildly, not sure if he was panicked or relieved that he couldn't find the giant fire bird.

"I don't feel any vibrations, other than ours and everyone in the tunnel." Toph said, looking thoroughly confused. "But I know Aang was still standing over there even after the tremors of fire crashing into the ground started. Then he just disappeared. Like he'd just floated into the air."

"You don't think he was incinerated do you?" Sokka asked, his panic winning as he turned wide eyed to Toph, not noticing the misery his words were causing his sister.

"No, I would know if that happened, even if it occurred quickly." Toph responded, shaking her head. "He just disappeared. Like when he'd just start floating in the Avatar State with no muscle movement to cause it. One second he's there, the next he's not."

"Then he's alive? But where is he?" Katara asked hopefully, standing up straight and looking up into the sky. "Aang? AANG?"

"Katara...he's not here." Sokka said softly, placing a comforting hand on her shoulder. "Whatever happened with that explosion, it sent Aang and the fire turkey somewhere else. That doesn't mean he's dead." He added quickly as tears resurfaced in Katara's eyes. "He's just somewhere else. It just means he's not here. We'll find him. And if the fire turkey has him, we'll find a way to take it out while we're at it. I promise."

Looking up into her brother's eyes and finding only reassurance and determination within them, Katara nodded, wiping away her tears. He was right, she knew it. Somehow, Aang was alive and he would be back. It would take a while to find him, she knew that in her heart, but she could wait. Gathering herself as the eclipse ended, Katara followed the others down the tunnel to tell everyone what had happened and to redesign their plans. After all, when Aang returned, he'd need help and a still reparable world if he was going to restore balance. The war was going to continue now that the Phoenix had disappeared too, and they'd missed their chance with the eclipse. It was now up to their rag tag invasion fleet to hold the fire nation at bay. And that was exactly what they'd do until the Avatar returned once more.