"So, this is your second Grand Trial?" Olivia asked.

"Actually, it's my first," Ash admitted. "When I went to see Kahuna Hala I mostly just tested how my new Grassnium Z was working."

"Oh, he mentioned that," Olivia realized. "I should have known it was you who'd used Mega Meganiumnium Z… anyway, this is going to be a battle with two Pokémon on a side. Is that all right?"

"Sure is!" Ash confirmed. "I'm all set!"

"In that case…" Olivia began, then sent out her Lycanroc and Probopass.

Ash replied with Salandit and Scrafty.

"Watch out for the Scrafty," Olivia warned. "Begin – Magnet Bomb! Accelerock!"

"Salac!" Ash called out. "Build it up!"

Scrafty dodged to the right, avoiding the high-speed barrage of rocks from the Accelerock, but Probopass' Magnet Bomb homed in to hit anyway – resulting in a cloud of smoke as Aten's illusion burst and sent him rolling over before skidding to a halt.

"Thought so," Olivia said. "I recognized him from before."

"Ow," Aten growled, then focused his attention on Probopass. "Revenge!"

Apparently it was specifically not just Probopass but the nose of Probopass which was coming in for Aten's ire, as he bit on and made the Rock-type float backwards with their mini-noses flailing to try and get Aten off.

"Help!" the Compass Pokémon called. "Ow! How is he biting so hard?"

"He's angry," Ash replied. "Just generally, but also specifically about this! He's that kind of Pokémon."

"Lycanroc, help Probopass," Olivia directed. "Rock Slide, he can take it and the Zorua can't."

Aten let go, pounced through Probopass in time to avoid the actual rock barrage, then looked back and forth for a moment and slapped the ground with his paw. That done, he darted to the side and hit it again.

"Stealth Rock," Olivia commanded. "Keep up the Rock Slide, Lycanroc. Magnet Bomb again."

Probopass flung out a Magnet Bomb which chased Aten around the arena, then Aten did a sliding skid and slapped the ground behind him with a paw- prompting a Fire Spin to shoot up around him, trapping him in place for a moment but also detonating the Magnet Bomb orb before it could reach Aten himself.

"Back in!" Ash said. "Keep it up, Salandit!"

"Keep what up, I wonder…" Olivia said to herself, frowning. "Lycanroc, Probopass, Salandit might be slowing you down. Are you feeling okay?"

Both Pokémon turned to their trainer and nodded, and Olivia thought hard.

Then Aten used Shadow Claw to slice an incoming rock in half, jumped up at Lycanroc, and hit them with Foul Play. That knocked the Rock-type to the ground, where one of Aten's traps detonated in a Sand Tomb.

"Now, Salandit!" Ash called.

Salandit smirked, flicking his tail up, and touched off the cloud of Salac-scented scent he'd been building up for at least the last minute.

The explosion made the whole battlefield jump, and more than that it was Fighting-typed – which meant it hit Lycanroc hard, hit Probopass very hard, and passed right through Aten as if nothing was there at all.

"Acceptable!" Aten called, as Lycanroc picked himself out of the shattered ground that had been the Sand Tomb. "Now do it again!"

"Stop Salandit from doing that again!" Olivia instructed.

"Protect Salandit!" Ash told Aten. "Smaller explosions now, Salandit, keep yourself safe!"

"Excuse me?" Aten asked. "I do not protect my teammates, they support me!"

He still attacked Lycanroc anyway, knocking their Accelerock off course, but that was presumably just a coincidence or something.

"She's giving me a smug smile!" Aten complained.

"That Salandit just blew up the whole landscape and you rigged part of it to turn into sand, why are you complaining about a smile?" Lycanroc asked, rolling over once before flinging a Rock Slide in the direction of Ash's Pokémon.

"He tried to bite my nose off!" Probopass added, flinging out a Zap Cannon.

"Disruption," Olivia commanded. "Probopass, Magnet Bomb, keep the Zorua from being able to defend."

"Aten!" Ash called. "Get ready!"

He held up his Z-ring, and Aten brightened.

"Go for Probopass!" Ash clarified. "They've got better battlefield control!"

"Probopass, get a Giga Impact ready to counter it," Olivia ordered, then blinked – because Ash wasn't doing the Dark or Fighting poses. "Wait-"

Aten pounced forwards in a swirl of spectral energy, and hit Probopass in an almighty explosion of rage.

Also ice. Quite a lot of ice.

"Huh, this one changed shape too," Ash said. "Hey, Aten, your one's got a little wispy flame symbol on it, so I guess that move is based on Bitter Malice specifically!"

"Good," Aten replied, wobbling around in a circle before falling over. "Nobody told me that would be that exhausting."

"Did you not hear me mentioning when I was exhausted after doing one?" Pikachu asked.

"That was you, not me," Aten answered, rolling onto his back and splaying his legs out.

Lycanrock and Olivia were both looking between Aten and Probopass, largely because the Compass Pokémon was frozen solid.

"Data observed!" Rotom said. "The Z-move acted like a Ghost type move but also like an Ice type move! I would like to suggest a name!"

"It's my Z move, I get to name it," Aten mumbled.

"Oh, my apologies," Rotom said, shrugging. "I thought you would appreciate the name Ice-Cold Royal Fury."

"...acceptable."

Probopass was out of the battle on account of being frozen entirely, since neither of Olivia's Pokémon had a fire move – it was actually up to Salandit to melt the Rock-type out again, whereupon Probopass went to sit on the sidelines – and Aten could technically still battle but he was almost completely exhausted.

"Tell you what," Salandit suggested. "Slap down some traps for me and we'll call it done."

"I accept," Aten decided. "I will technically have done more than half the work in this battle, and therefore the win is mine alone!"

"Sure, whatever," Salandit decided, shrugging.

"Ready to resume?" Olivia checked.

"Yeah!" Ash agreed.

"Rock Slide!" Olivia commanded, and her Lycanroc fired a barrage of rocks at Aten.

The Ghost-type just about managed to dodge from the first one, then Salandit set off a cloud of Fighting which burst the rest, and Aten gamely laid down two or three more traps to go with the ones he'd already made – then Lycanroc used Accelerock, and knocked Aten off the battlefield.

Ash recalled him, already deciding to ask Dragonite to make one of those old Pokemon-shaped flavoured loaves that Aten didn't admit to liking, then returned his attention to the arena – where Salandit was blowing out clouds of scented smoke and trying to catch Lycanroc in them.

It wasn't going well, but at least it wasn't going well for either Pokémon.

"Salandit, try making a differently shaped cloud!" Ash called, frowning. "Um… right, yeah! So make a cloud of Pamtre in a half-sphere shape!"

"A half sphere?" Salandit repeated. "Wow, uh… okay, I'll give it a try-"

"Look out!" Ash interrupted, and Salandit ducked as Lycanroc pounced just overhead.

The Rock-type summoned a Rock Slide, flinging it at Salandit, and Salandit darted inside a cloud of Salac he'd already set up and touched it off. The explosion shattered the incoming rocks, and Salandit exhaled a sigh of relief before spinning out a replacement Liechi cloud and getting to work on the Pamtre.

"What are you planning?" Pikachu asked.

"I don't know how well this works, but I think it will!" Ash replied. "Actually – make a whole sphere, that'll be easier! Then line it with Watmel, and get ready to do some Lansat!"

"I don't want to see what this is going to be," Olivia decided. "Lycanroc, Continental Crush!"

She struck the first pose, then the second, and Lycanroc began glowing with energy before leaping into the air and using Rock Slide.

"Chop the top half off your sphere with Lansat!" Ash said, as the rocks began to gather together into Continental Crush, and Salandit did just as he was ordered – slicing the sphere so only half of it was left. "Now, underneath and light the Watmel there!"

Pikachu put his paws over his ears.

The explosion of the Watmel turned into fire, which lit off the Pamtre-flavoured scent. Since it was being pressed on from all the directions below it, it turned into an upwards facing jet of silvery Steel-typed light, and smashed into the descending Continental Crush with a massive wham sound.

That didn't destroy the incoming attack, even though it shattered it into pieces, and the air filled with dust and rock flour as Lycanroc sent what was left crashing down on top of their opponent.

"Wow," Rockruff said, seriously impressed. "I wonder if I'll be able to do that!"

Then one of the rocks heaved aside.

"Well," Salazzle said, inspecting himself as he put the rock down. "That's odd. Didn't know that was possible."

"Huh, that is weird!" Ash agreed. "Ibid, any ideas?"

"Checking," Ibid replied. "Some of the files I have available say that male Salandit do not evolve because they give the females most of their food."

"Yeah, tell me about it," Salazzle grumbled. "Just because I wasn't interested I got so much shade from the others… you would not believe."

He shrugged. "Still, there you go. We going to keep going?"

"You weren't interested?" Lycanroc repeated, trying to shake off post-Z-move exhaustion. "I… it says a lot about how today has gone that… that's the thing I'm questioning."

"Yep, that's me," Salazzle said. "The aromatic aromantic. Are we going to keep battling?"

"I think that's it for our battle," Olivia decided. "Mostly because I don't think Lycanroc can keep battling, partly because Professor Kukui should hear about this…"

AN:

The unfortunate thing about an evolution that's never happened before is that it's very hard to work out the trigger conditions.

Eating lots of food. A wide variety of berry scents. Being a Totem Pokémon. Ash's proximity. Being beaned by the fragments of a giant rock.

Could be anything.