Shiranui walked out onto the battlefield of the Stow-on-Side Stadium and saw a dark grey-haired boy wearing a mask.  "Allister, I presume?" Shiranui asked, earning a nod from the masked gym leader, "Whilst I like your mask, O ye of few words, here's a breakdown of what's happening: one, you're facing a challenger you yourself endorsed—something few gym leaders past Kabu go through; and two, I'm not like most challengers as I can tell how people like you think."
"…A-are you sure?" Allister questioned with glowing purple eyes lighting up in his mask, "I may not be the first Ghost type gym leader you defeated, but I have some tricks of my own.  H-here…I go…"  With that, Allister opened with a Yamask, which Shiranui scanned with his Rotom Phone.
"[i]Yamask: Galar Form, the Spirit Pokémon.  A Ground and Ghost type.  It's said that this Pokémon was formed when an ancient clay tablet was drawn to a vengeful spirit.[/i]"
"Sogekishu, I choose you!"  Shiranui sent out his Inteleon and the match was underway.  "Start with Scald!"
"Yamask, Disable!"  Sogekishu fired a jet of scalding hot water from his finger gun and blasted Yamask for enough damage to knock it out with one hit.  "Yamask, return; Mimikyu, you're up!"  Allister swapped his fallen Yamask for a Pokémon that was familiar to Shiranui.

"Mimikyu, Shadow Sneak!"
"Sogekishu, Aqua Jet!"  Both Pokémon charged at each other; in Sogekishu's case the Inteleon was a saurian water missile.  Mimikyu's attack did minor damage and Sogekishu's attack broke Mimikyu's Disguise.  "With that formality out of the way, Sogekishu, give Mimikyu a shot of your Shadow Ball!"
"Mimikyu, Slash at Inteleon!"  Sogekishu fired a Shadow Ball and landed a hit that Mimikyu barely survived.  Mimikyu took the opportunity to slash Sogekishu for a big hit.  "Mimikyu, Shadow Sneak!"
"Sogekishu, finish Mimikyu off with a Snipe Shot!"  Mimikyu came out of Sogekishu's shadow and struck the Inteleon for a critical hit that Sogekishu barely survived.  The Inteleon pointed a finger gun at Mimikyu and shot a powerful jet of water at point blank range.  Mimikyu fainted dramatically from the hit.

Allister swapped out the downed Mimikyu and sent out a Cursola.  Vaguely recognising the Pokémon, Shiranui scanned it with his Rotom Phone.  "[i]Cursola, the Coral Pokémon.  A Ghost type and the evolved form of Corsola: Galar Form.  Be cautious of the ectoplasmic body surrounding its soul.  You'll become stiff as stone if you touch it.[/i]"
"Sogekishu, Shadow Ball!"
"Cursola, finish off Inteleon with Hex!"  Sogekishu managed to get off one more Shadow Ball shot before getting assaulted by Cursola's Hex and fainting from the powerful hit.

Shiranui switched out his downed Inteleon and sent out his Meowstic.  "Cursola, let rip with a Hex!"
"Nekomata, finish Cursola off with a Night Slash!"  In spite of Cursola's Weak Armor ability boosting its speed, Nekomata powered through the Hex it resisted and through ninja-like trickery, popped out behind Cursola as the Zoroark he was and slashed a "Z" on Cursola's back, causing the bleached coral to faint from the hit.

"My very last Pokémon… How lonely… How frightening…" Allister commented as he sent his Gengar out in lieu of his Cursola.  "G-Max Terror…  It's like Shadow Tag…  You won't get away…  I won't let you!"
"Zoro, Dynamax and use Max Darkness!"  Both Allister and Shiranui recalled their Pokémon, activated their Dynamax Bands and threw their respective enlarged Poké Balls back towards the rear of their sides of the battlefield.  Two Dynamaxed Pokémon emerged with the Gengar in its Gigantamax form.  Lots of large objects flew at Zoro and did some damage.  Zoro in response conjured a large dome of dark energy similar to his signature move around Gengar and caused a devastating amount of damage, making Gengar revert to its base form and leaving it prone.

"I nearly lost my mask from the shock…  That was…wow.  I can see your skill for what it is," Allister commented as the eye lights in his mask went out, "Here…  A Ghost Badge…"