(Before getting into detail, this is a simple What-If scenario that has no baring on Crossing Over, or any AU at all. Also, there may be potential spoilers for Pokémon Scarlet and Violet. Specifically the last story in the base game. Make sure you've played either game first. Thank you for reading.)

One seemingly normal day, Kat and Ben were relaxing before they ended up getting an assignment to a normally forbidden location within the Paldea region itself. That area being Area Zero, within the Great Crater of Paldea. They were filled in on how dangerous it was due to not just powerful Pokémon living within it, but also because it was filled with both ancient and future Paradox Pokémon. And that the assignment was to see if rumours of an additional ancient and future Paradox being discovered and roaming around were true. Once they were made aware of the potential dangers, they grabbed their Pokéballs which contained their Pokémon to help protect them after arriving.

Once they arrived in Paldea, and traveled all the way down to Area Zero itself, Kat brought out Bruiser. His Incineroar known for being blue where the average one would have red instead. Ben meanwhile thought about who to bring out, but ultimately settled on bringing out his Greninja. His Greninja wore a neo street style attire compared to the average Greninja ever since he was a Froakie, and had quite the potential for battling due to his place of origin.

Kat and Ben soon descended down Area Zero with their Pokémon on the lookout as bodyguards. And soon they arrived at the spot at one of the area levels where the rumoured sightings were. It apparently looked like it would've been just that, rumours. But then... Bruiser and Greninja sensed hostile presences as they became protective of their respective trainers. And just like a flash, they intercepted an attack, pushing the agressors back even though they managed to get a hit on and injure both trainers!

Once Kat and Ben were able to see who their attackers were, they were stunned to see Paradox Pokémon looking similar to the favourites they had on hand right at this moment!

In front of Kat's eyes, there was a smilodon-like Incineroar confirmed to be known as Singeing Fangs. Whose saliva contained a material that inflicted a burning sensation on the skin. No doubt that was very painful for Kat, especially with his cuts. Meanwhile in front of Ben's, in front of him was an android resembling Greninja confirmed to be known as Iron Infiltrator. This Paradox Pokémon was made to be the ultimate assassian. Having a built-in cloaking system to blend in with its surroundings, and being able to take out enemies with its whip-like cable tongue, or even conjuring up shurikens of water via the mosture in the air with gravity manipulators built into its palms.

This was one battle that the two Pokémon would have to win, especially to protect their injuried trainers! Bruiser had the idea of going toe-to-toe with Singeing Fangs, even grabbing the ancient Paradox Pokémon's tusks with his claws to prevent any biting which could inflict harm on either himself or Kat! Greninja mean while would keep up with Iron Infilitrator with his speed, even being able to dodge the future Paradox Pokémon's attacks with swift reflexes and even using Substitue, even not minding his attire being blown away during the scuffle. Since protecting Ben was more important to him.

Luckily for the two trainers, their faith in their Pokémon would pay off. As Bruiser and Greninja were able to fend off and defeat their Paradox counterparts, before all of them eventually escaped and reported back home with official confirmation that the rumours were real. And they were able to present proof while having their injuries being tended to. As well as their Pokémon getting treatment and rest as well.

Though considering those Paradox Pokémon were never seen until now... What else is lurking within Area Zero? Certainly leaves a mystery up in the air.

And now... Additional info on the Paradox Pokémon.

Singeing Fangs
Type: Fire/Poison
Ability: Protosynthesis
Scarlet Pokédex Entry: Sightings of this Pokémon were scarce. An old entry mentions despite its agression, it will not harm and even protect children.
Violet Pokédex Entry: It was mentioned in a paranormal magazine to resemble Incineroar from billions of years ago, albeit walking on 4 legs instead of 2.

Iron Infiltrator
Type: Water/Steel
Ability: Quark Drive
Scarlet Pokédex Entry: Reported from an paranormal magazine by its resembalance to Greninja. It was said to be created by an ancient civilisation, or a mecha lover.
Violet Pokédex Entry: It was a rare ocassion for a sighting of this Pokémon to be reported. Supposedly, it was created to become the ultimate warrior, but became more than that.

Ben Fuller, Ben's Froakie (Mentioned)/Greninja and short story belong to  BenSullicoot

Kat, Bruiser the Incineroar and art by  AnonymousKat

Singeing Fangs and Iron Infiltrator are original Paradox Pokémon created by  AnonymousKat

Substitue Doll, Froakie (Mentioned), Greninja, Incineroar belong to the Pokémon franchise. Their Paradox Pokémon counterparts though fanmade, the concept still belong to the same franchise as well.