The site of the mysterious demonstration was a laboratory called the Mirage Mansion, one built like a castle by the side of a lake, and the researcher – Doctor Yung – greeted them outside with a smile.

"Welcome!" he said. "Arriving in style, I see."

"You know how it is," Professor Oak replied. "When you're offered a ride by several Dragonite, it's only polite to agree!"

Yung chuckled. "I don't know how it is, but I can see how that would work," he said. "And you must be Ash Ketchum?"

Tracey looked confused. "Uh… no, actually. That's Ash."

"It is?" Yung asked, then looked terribly embarrassed. "Oh, dear… sorry about that."

"How did you confuse them?" Max asked. "They look pretty different."

Yung chuckled, adjusting his glasses. "In all honesty, when I watched the recordings of his battles I was mostly focused on the Pokémon."

"Like me?" Pikachu asked, waving. "I'm a useful pointer."

"My goodness," Yung said.

Then he shook his head. "Well, come in, come in!"

Yung let them into the expansive courtyard of his lab, and explained how he had single-handedly invented something called the Mirage System – a mixture of computer simulation and hologram, plus the concepts behind the digital manifestation system that allowed a Porygon to exist in the real world.

"The practical upshot of which is," Yung explained, "I can make virtual Pokémon that appear right here! I call them Mirage Pokémon, because they're not real, but they're still quite formidable!"

A tap on a control tablet, and a slightly misty looking Aggron appeared in front of them.

"Voila," Yung said. "And, because it's a virtual creation based on data, I can give it moves an Aggron wouldn't normally have."

Max nearly fell over laughing.

"Is something wrong?" Yung said.

"Oh, just the idea of that being unusual," Max explained. "Sometimes I get a reminder like that and it always feels weird when it happens."

"Can you do really rare Pokémon?" Ash asked. "Like Pidgeotto?"

Yung stared at him, then turned his gaze to Oak.

Oak spread his hands. "It's the Ash Ketchum experience," he said.

"Actually, can that Aggron do Surf?" Ash said.

"Of course it can!" Yung agreed, typing on his tablet, and the Aggron moved.

"Aggron," it said, and exhaled a jet of water.

"That's not what I think of when I think of Surf!" Pikachu announced. "What I think of when I think of surf is this!"

He jumped down from Ash's shoulder, and landed on a shimmering watery surfboard.

"See?" he said. "Much more versatile."

"That's remarkable," Yung breathed.

"Um… Doctor Yung?" May asked, raising her hand. "Do you have a relative who judges Contests?"

"What?" Yung said, distracted. "I don't? Think so, I mean? Why do you ask?"

"Just curious," May told him.

"And, well… the Mirage System is an excellent simulation, but it needs data," Doctor Yung resumed. "I can't do a Pokémon or move I don't have data for."

"What about if you got data from my Pokédex, Ibid?" Ash asked. "He's got plenty of data! Though not on a lot of the Legendary Pokémon, because we last saw several of them in Johto or the Orange Islands."

Doctor Yung was happy to accept, and loaded the data from Ibid into the system.

"There's also a way I can get information from the memories of a Pokémon," he said. "It is a bit painful, though."

"Ehh…" Pikachu said. "I'm the only one who's been around for all of it, I think. And pain sounds… painful."

"That would be a shame," Yung sighed, paging through his tablet. "...there's more here than it sounded like…"

Then the lights went out, plunging the room into darkness.

"What just happened?" Tracey asked.

Brock sent out Lotad. "Flash!"

Lotad's lilypad lit up, illuminating the room, and Doctor Yung froze halfway through changing into a costume.

"...drat," he said, then stabbed a button on his control pad.

A dozen Mirage Legendaries appeared all at once between him and the friends, the lights came back up, and most of the humans stepped back while Pokémon emerged from their Pokéballs and Ash got a Razor Wind ready.

"Hey!" Pikachu said, cheeks sparking. "What's the big idea?"

"You have to understand, I need that data," Yung said. "It's the only way to make the Mirage System as complete as it was always meant to be – then people will have to respect my research!"

In Dahara City, Hoopa cracked Hoopa's knuckles.

"Hoopa now sees that the Unown were a practice run!" they declared. "Allez Hoopa-Rings!"

Zeraora yowled in surprise as a portal opened directly underneath him.

Twisting in mid-air, the Electric-type landed on his feet, then looked up – though the golden Hyperspace Hole had already vanished, leaving him with nothing to shake his fist at.

"Not this again!" he groaned. "What's going on?"

"Something about mirage Legendary Pokémon, I believe," Azelf said. "I don't know for sure, knowing for sure isn't my department."

More and more Legendaries landed around them, or appeared in mid-air and began floating over the lake, while dozens of misty-looking Mirage Pokémon appeared as well.

"Well, then…" Zeraora said, fists crackling with lightning. "What are we waiting for?"

Yung brandished his tablet. "Don't try anything! I can make these Legendary Pokémon use any attack I have data for!"

He flicked his finger across it, then hovered over a button. "Do you want to see what happens when a Mirage Latios uses V-Create?"

There was a faint shwinng, and his tablet fell apart – sliced neatly into two halves.

"Not really, no!" Purrloin said, tail returning to a ready position. "Oh, sorry, I should have said. Shadow Force."

Yung looked at the tablet, then at Purrloin.

Then kicked her.

His shoe went straight though the Ghost-type, and she folded her forelegs. "Rude!"

"Don't you realize what you've done?" he said. "Without my controlling them, all the Legendaries I summoned outside – they're acting on instinct and there's no way to stop them! You've made things so much worse!"

"That doesn't sound good," Max opined.

Brock pointed. "Crobat! Tie him up – we need to get outside!"

With Ash in the lead, the friends rushed outside.

They were too late to prevent anything, though. All over the valley were Legendary Pokémon embroiled in desperate struggles.

"No, no, no!" Tapu Koko said, arms on his hips. "If you're going to do this, you need to do it right! Start moving when the starting signal happens, and not a moment before! Otherwise it's not a fair competition!"

"But-" Zeraora began.

"I insist!" Tapu Koku insisted. "Back to the start line! And you as well, Mirage Deoxys, I saw you doing that…"

The virtual Deoxys floated backwards slightly.

"That's better," Tapu Koku said. "Now, remember, it's three, two, one, and then the word go. The starting signal will happen, and that is when you need to start running. Not before."

"You've explained this twice already," Zamazenta sighed. "Are we going to get on with it?"

"I sincerely hope so," Tapu Koku said. "Mirage Regieleki! If you do that again you will be disqualified!"

Out on the lake, a tower of ice blocks collapsed.

"That was your fault!" Reshiram insisted.

"How was it my fault?" Kyogre replied. "You're the one with a jet turbine in his tail! How do you know you didn't melt any of the blocks?"

"Because what I said is Truth!" Reshiram countered. "Now, hurry up, Zekrom and Mirage Reshiram are already onto two storeys high!"

"It's not how fast you build the ice tower, it's how high it is when the time runs out," Kyogre rumbled. "So we need to do this well. Not quickly, well."

"That's nonsense," Reshiram said, notably not making a statement on whether it was True.

At a path by the lakeside, Lunala's wings beat as she pulled a cart around a hastily-constructed racetrack.

"Remember, two laps and then we switch!" she said. "Don't forget!"

"I know," Solgaleo rumbled. "I wouldn't forget that bit of the agreement."

He twisted in the cart slightly, then blinked.

"I think you might need to speed up," he warned. "There's a very non-regulation cart coming up behind us!"

"How bad can it be?" Lunala asked, coasting for a moment so she could turn and look.

Did a double-take.

"Okay, we need to speed up!" she agreed. "Who put a giant drill weapon on a pinewood cart?"

"I'll give you two guesses and they rhyme with Barkrai and Ziptini!" Solgaleo replied. "Whoops – don't run over the one with Mirage Zamazenta in!"

"All right, all right, don't fuss," Lunala retorted. "Sharp left turn ahead!"

Yveltal raised a wing. "I have a question."

"Go ahead, Yveltal," Tornadus invited. "What's the matter?"

"Who came up with this task, exactly?" Yveltal said.

"I think it started as a rocketry contest, but someone pointed out we didn't have any rockets," Tornadus said. "And then it sort of went from there. Now, hurry up, some of the others are already making their entries."

Even as he spoke, a Mirage Therian Landorus chopped down a tree with its tail and then threw the entire tree across the lake.

"Eight!" Tapu Bulu judged. "Fine throw!"

Shaymintwo snorted.

"I don't need to take part in a competition involving fakes," he said.

"Umm…" Keldeo began, raising a hoof uncertainly. "Aren't you literally a clone?"

"It's not the same," Shaymintwo declared.

"Then do you want to come and judge the art competition?" Keldeo suggested. "Cobalion wasn't interested at first, but Terrakion made him a twelve foot block of granite with Stone Edge and I think he's taken to sculpture."

"Tch," Shaymintwo said, rising to his paws. "If I'm going to get involved in an art competition it's going to involve something with spikes."

"Oh, a self portrait?" Keldeo asked.

"...sure, why not," Shaymintwo decided.

"Well, in all honesty, this does fit with what usually happens when there's large numbers of Legendaries around," Pikachu said. "Is that instinct? It feels like that's instinct."

Then a familiar-looking pink kitten popped in next to them.

"Hi!" it said. "And thanks for your help! Do not worry, the Mirage System is now no longer dangerous."

"Who are you?" Ash asked. "You're not a Mew I've met before."

"Correct!" the Mew declared. "I am the Mirage System. Any sufficiently advanced method of storing Pokémon is indistinguishable from a Pokéball Registration System, and according to recently acquired data Mew are extremely good at hacking."

"I think that's just one specific Mew, but they're very good at it," Max said. "And if you got all that data from Ibid, that would be the one."

"I've been meaning to ask about that, actually," Professor Oak said. "You called your Pokédex Ibid?"

"Yeah, I got him from Mew at the end of the Silver Conference," Ash agreed. "I think he's a Pokémon of some sort… I've still got the old one somewhere."

"I swear, keeping up with you is a full time research project," Oak grumbled.

The Mirage Mew giggled.

"Did you know that the Mirage System can simulate arbitrary structures with sufficient data?" they said. "Including power systems and Mirage System projectors? I would quite like to have backups somewhere but I intend to leave the Mirage Mansion and can do so under my own power. Do you have advice about how to sort out my legal situation?"

Ash thought about that for a moment.

"I can call Lance and see if he can help?" he suggested.

AN:

Oops, looks like you tried to throw down illusion wise with Ash.