Listen up, because I'm only going to say this once: I do not own Lilo and Stitch, or any of the characters used in this fic. They belong to Chris and Dean. The only exception is Experiment 623, whose original idea is owned by me.

Chapter 1: Aloha

'Lilo!' a shrill voice called from the living room. 'Get in here, quickly!'

Lilo scooted down the hallway as fast as she could. 'What is it, Pleakley?'

Pleakley replied in a mock-calm tone. 'Oh, I just thought you'd like to know that something is tearing up the streets downtown. It's all here on the news, and the worst part is, I'm missing my soap operas for it!'

Lilo ignored him and turned her attention to the television.

'…where everything is being destroyed. People have abandoned their attempts to stop the unknown force which is tearing apart the town, and have decided that fleeing is a better option. As far as we can tell, nobody has been hurt, although many people have been found confused and disorientated. They claim that the wreckage was caused by some sort of small animal, something like a koala…'

In the corner of the screen was a live film clip showing the awful state that some buildings were in. Many things were on fire, and it wasn't long before some flaming debris crushed the camera, cutting out the picture.

'Stitch!' Lilo cried, while running to the front door. 'Come on, we've got an experiment out there to catch!'

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A few minutes later they arrived in town, Stitch driving the red vehicle which used to be Nani's dune buggy. All they had with them was a reinforced experiment container held in place at the back of the car.

'All right, let's rock-a-hula, Stitch!' Lilo encouraged, getting out to release the container. While she did that Stitch started out looking for one of his 'cousins'. He climbed up a nearby wall to begin exploring the wrecked town, reverting to his original alien shape as he did so. It was one of Stitch's basic rules: when in doubt, use all four arms. Not that it mattered, there were no humans around to see.

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Lilo left the buggy and started to look around, holding the empty canister. She didn't have to look too hard, in this situation it was Stitch's job. Nearly everywhere was blocked off to her because of fire or a broken building, but for Stitch this wasn't a problem. Still, she did start to worry about him. They had no idea what kind of experiment this was, and so had been unable to bring along some of Jumba's gadgets. She looked around; not too much had been destroyed, but quite a few things had gone up in flames. She shook her head and reassured herself. Nothing could beat Stitch anyway, nothing ever had, with the possible exception of 627, and he was safe and dry as a pod where no water would ever reach him.

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Stitch's excellent hearing finally picked up something. He headed immediately in that direction, climbing down a wall and continuing on all sixes. An explosion went off nearby, and once the resonating blast stopped clouding his senses he could hear the creature even more: a few footsteps, and scattered breathing. He turned into an alleyway, knowing whatever it was lay around the next corner. He jumped out to confront it and growled.

For a few moments nothing happened. The experiment was facing away, and then it slowly turned around.

Stitch immediately recognised this experiment as a girl. She looked quite similar to Stitch, and most of her fur was a flaming reddish-brown, with a darker pattern of splotches on her back. The fur on her front and around her eyes was a rich golden yellow, and the skin inside her ear was pale tan. Her nose was a deep velvety brown.

She remained there, frozen, for some time. All four of her arms were extended too, along with brown spikes and red antennae which had the same yellow on the ends. Lots more fur grew at the top of her chest, which puffed it out a lot more than normal. Her ears were larger than his and were more petal-shaped, very pointy at the ends. More fur grew on her head in a tuft like a fringe, and under that between her black eyes was an unmissable feature: two short, pearly white horns. Each was only about 3 centimetres long, but they looked very sharp.

Stitch thought that he should speak, but paused. He was sure that when she first turned around she looked fierce, but now her expression was relaxed and she seemed quite tame.

'Hello,' he tried, expecting her to attack, or fly into another rage, but instead she simply walked over and looked at him with her head on one side and her eyes questioning.

'Hello,' she repeated, her voice the same as Stitch's but higher.

'Um… Lilo!?' he yelled, hoping she was nearby. Within a few seconds she reached them.

'Hey, great, you found it!' she said, opening the container. 'Er… didn't you have to fight it, or anything?'

'Naga,' he said, sounding quite surprised. Suddenly a great thump shook the ground, followed by another.

'Oh no!' Lilo said. 'Gantu's coming! Quick, you,' she asked, gesturing to the newcomer experiment and holding out the tube, 'get in here, please.'

Stitch looked back at her in wonder. She was brown. Brown? Hadn't she been more reddish when he found her?

She looked at him with a questioning expression, as if asking whether she should do it.

'Ih,' he said to her. 'Go, please.'

In a flash she nipped inside the clear tube. Stitch carefully picked it up and closed the end, then carried it as he and Lilo ran back to the buggy.

'Hurry!' yelled Lilo, as the ground-shaking footstep grew closer. 'Gantu's getting closer!'

Stitch hurriedly attached the container with the new experiment inside it to the rear of the vehicle and hopped into the driver's seat.

The buggy started up and screeched off, but not soon enough. A green plasma blast hit the ground where they had been parked and shook the car.

Lilo turned in her seat. The brown experiment was behind her in the canister, sitting with her nose pressed against the glass and not looking scared at all. Behind that was Gantu, running up and following the buggy as it sped away. The buggy might have been fast, but it had to slow down to swerve around debris in the road and, after all, Gantu had very long legs.

'You! Abomination!' he shouted. 'Come back here with that… other abomination!' He was only just keeping up as Stitch drove the car as fast as he could, and Gantu fired two shots from his blaster. Stitch swerved to avoid them.

'Go home, Gantu!' Lilo yelled back. 'This one's coming with us, so we can find the one place that it belongs!'

Another plasma shot. 'I'd like to see you try!' Gantu retorted. 'That experiment is made only for destruction! You'll never find a home for it!'

Three shots. The last one was very close. Gantu was catching up.

'That's not true!' Lilo kept shouting. 'Experiments can do whatever they want!' she finished, stressing the last three words. With that, Stitch found an opening on the road and pulled ahead. Gantu finally ran out of breath and collapsed.

Back at Lilo's house, the three of them went up to Lilo's old bedroom to see Jumba about the analysis of the experiment.

'Oh, little girl, you are back,' he said as they entered. 'Which of my genius experiments have you brought back this time?' He had already switched on his computer and was sitting at his desk.

Lilo walked in and watched as Stitch and the new one came in. They both went to sit on the top bunk, Jumba's bed, while Stitch showed her where to go and she just looked at everything in wonder.

'Oh!' Jumba exclaimed. 'Experiment 623! I was wondering when she was going to turn up,' he turned to the computer and began typing in numbers.

'She?!' Lilo exclaimed. 'That's a girl?'

'Ih!' said Stitch from the bed, sounding rather annoyed.

'Aha! Here it is,' Jumba turned the computer towards them. It showed alien letters scrolling on one side and a diagram of the experiment in question, a simple picture which seemed elegant, but had more prominent horns depicted on the head.

'Experiment 623,' he explained, 'has potential to be most destructive of all the experiments.'

'What? You mean, more destructive than Stitch!?' Lilo asked, just as Pleakley entered the room.

'Oh, you're back,' the one-eyed alien remarked. 'Is that it? That's the terrible force that was tearing up the town earlier?' He walked over to 623, still resting on the top bunk. Before anyone could stop him, he reached out a finger to tickle the experiment.

The reaction was immediate. Stitch looked in amazement as her fur went red again. She scowled at Pleakley and, quick as a flash, her teeth sunk into his hand.

'Yaaaaaaaaaaargh!' Pleakley screamed, whipping his hand away. She seemed amused at his reaction and laughed, as the redness drained from her body and it became brown again.

'Pleakley! Are you okay?' exclaimed Lilo.

Pleakley nursed his swollen finger. 'Well, it's not as bad as when the little monster chomped on my head.' He turned stiffly and walked out of the room.

Jumba coughed impatiently at being interrupted. 'Allow me to be continuing. 623's power comes from her anger. The angrier she is, the more destructive she gets. And believe me, is very easy to make her angry.'

Lilo looked at the small brown experiment looking in wonder at the bed sheets.

'She's not being destructive now,' she observed.

'No, at the moment she is not being angry. But you see what happened to Pleakley? She got a little irritated,' Jumba paused and laughed. 'But do not underestimate 623. She did not work out as well as I had hoped. When she is very mad, has strength greater than 626's, can breathe fire, and cannot be reasoned with. Will go on great fiery rampage. Her purpose is to destroy just about everything, because she is so strong and many things are flammable. But there were problems. I found anger induced strength was far too unpredictable for proper use, and was no good for attacking cities. Buildings don't burn.' He laughed again and looked at the bed.

'That is why I made 626. He can destroy the cities and civilisation, and she tears apart everything more natural. 626 is not as strong as she could be in right situation, but his power is there all the time, so is improvement.'

'Gantu said I'd never think of a home for her,' Lilo said. 'Because she's too destructive. But Stitch was too, and we found a home for him here, so I know I'll be able to think of something for -,'

'Gaba?!' she was interrupted by 623 shouting from the bed.

'What's going on?' asked Lilo.

Jumba laughed. 'Stitch just told 623 about planet she has been activated on. She didn't like the fact that over 70% is covered by water.'

Lilo sighed. 'So she's afraid of water too?'

'Yes, of course, many experiments are. The molecular density of their bodies which makes them sink in water is due to their massive physical capabilities.' He saw that look that Lilo put on when she didn't understand a word. He sighed in desperation, 'All experiments with unnatural strength have muscles too dense to float. If it can pick up a car, would sink like stone.'

'But you said her strength is only there sometimes.'

'Ah, yes, is true. Perhaps 623 only sinks when she has her strength…but there is other problem. If this experiment reached maximum level of pure anger, might be too much power concentrated and could have big disaster!'

Lilo was scared now. 'Could it endanger the Earth?'

'No, no, not a problem for that. Is a danger to her. That much power could overload her body and it could shut down completely.' He paused and continued in a more relaxed tone, 'I have never thought it would actually happen though. To become that strong she must feel the most powerful anger that is possible. Such a feeling could only come out if it was found in a sincere place inside her, and be connected with something she cares about. I didn't worry because she isn't made to care about anything,' he chuckled.

Lilo looked again at the brown furball sitting on Jumba's bed. She seemed more curious than angry, and was inspecting the light on the ceiling. She then walked across the ceiling to it and tried to eat it.

'I would suggest that you try and turn experiment to good first.' Jumba remarked. 'Before she eats anything else.'