Liam went first. Milo stood center field in a stadium with a big smile.     
      "My Gym’s the first one people face, so we get a lot of challengers. I've heard about you from Leon. Sure seems like you understand Pokémon real well. This is gonna be a doozy of a battle! I’ll have to Dynamax my Pokémon if I want to win!" The jumbotron lit up and showed Milo and Liam on it with two circles, both of which were currently blank. Milo then informed Liam they would both get to use two Pokémon, and sent out his first one, Gossifleur.

"[i]Gossifleur, the Flowering Pokémon, A Grass-type. It anchors itself in the ground with its single leg, then basks in the sun. After absorbing enough sunlight, its petals spread as it blooms brilliantly. It whirls around in the wind while singing a joyous song. This delightful display has charmed many into raising this Pokémon.[/i]"

"OK, Go! Rookidee!" Liam declared sending out the shiny Pokémon.
 "Use Peck," Liam declared. The yellow bird dive-bombed toward the Grass-type. and began pecking at it. 
"Use Sing," Milo said. Gossifleur began singing a song and Rookidee crashed to the floor asleep.
Liam chuckled as he began rummaging through his bag while keeping his eyes on the battlefield, pulling out the pokéflute he was given once upon a time by Mr. Fuji in Lavender Town. Liam played a familiar tune on the flute on Rookidee woke up.

"Sweet Scent!" Gossifleur unleashed a pleasant aroma to lower Rookidee's evasiveness.
"Hone Claws!" Liam ordered. Rookidee sharpened his talons, upping his attack and accuracy.
"Rapid Spin," Milo called. His Pokémon spun into Rookidee it scored a direct hit on Rookidee, who was knocked back down to the ground.
 "Use Pluck!" Liam called. Rookidee became airborne again and rocketed toward its opponent, scoring a direct hit and getting a KO

"Gissifleur is unable to battle, Rookidee wins!" called the Rotom Ref. The small in stadium crowed cheered as Milo recalled Gossifleur, prasing it for the good work.

Woohoo! We’re not going to be done in that easy! We’re tough as weeds! Go, Eldegloss!"

a small green pokémon with what seemed to be a huge ball of cotton on its head emerged. 

"[i]Eldegoss, the Cotton Bloom Pokémon a Grass-Type, and the evolved form of Gossifleur. The seeds attached to its cotton fluff are full of nutrients. It spreads them on the wind so that plants and other Pokémon can benefit from them. The cotton on the head of this Pokémon can be spun into a glossy, gorgeous yarn—a Galar regional specialty.[/i]"

"Want to keep going Rookidee?" Liam asked.
 "Rook!" The bird chirped happily.
 "Alright, we'll keep going."

Milo smirked. "Come on, then! It’s Dynamax time! You’re about to be uprooted!" He recalled Eldergoss to its ball and activated his Dynamax band. The ball grew several times larger and Milo tossed it, revealing that the Pokémon had grown many times bigger.
"This’ll really leave you in shock and awe. It’s our Dynamax move!" Milo then instructed his Pokémon to use Max Overgrowth. The attack, despite being not very effective KO'd  Rookidee tieing it up.
"OK Beckham, it's up to you!" Liam declared. Beckham, who had been standing on the sidelines, wanting to see the stadium for himself ran out to take his position.
(Milo Dyna 1)

Liam Dynamaxed Beckham. Milo called for Max Overgrowth again and Liam called for Max Flare. Beckham set fire to the grass that had grown in from the grass move, Beckham landed a critical hit and KO'd Eldegoss. Beckham returned to his normal size and began to glow white after taking a victory pose.

"Raboot, the Rabbit Pokémon. A Fire-type and the evolved form of Scorbunny. Its thick and fluffy fur protects it from the cold and enables it to use hotter fire moves. It kicks berries right off the branches of trees and then juggles them with its feet, practicing its footwork."

Liam ran over and hugged Beckham in delight for its evolution.

Liam turned his attention back to Milo to thank him for the battle and shake his hand. 
"The power of Grass has wilted... What an incredible Gym Challenger! That must have been a fulfilling Pokémon battle for you!" As proof that you have defeated a Gym Leader for the Gym Challenge, allow me to present you with your very own Grass Badge! You need to obtain all eight Gym Badges in order to complete the Gym Challenge. And the only way to gather the Badges is to defeat every Gym Leader!
    "Some advice for you, Johto Champion, Coleman. The Gym Challenge has a set order you’ll need to follow. So that means your next stop should be in Hulbury to meet Nessa. Hulbury’s just beyond Route 5."

Liam thanked Milo and received the Grass Badge. Milo used a healing machine to restore his and Liam's Pokémon and came back to fight the next challenger.