You take a stance, readying yourself for battle and glaring at the other Wartortle, hoping you at least look as tough as him, despite feeling ridiculous standing here like this, preparing to face down your mirror image.
"Okay, water gun!" she yells, and your opponent opens his mouth wide and then starts squirting at you. The jet probably would have worked too, had you been just about any other type of pokemon, but since you're a water type too it barely registers, and thinking quickly you find that this particular Wartortle knows the move, Headbutt.
Smiling you realize this girl is either a new trainer, or just one that's forgotten the basics, and intending on showing her you lean your head back, her shout telling you she thought the attack of her pokemon was working, at least up until the point where you vaulted forward, your skill glowing as you rushed through the air.
Your momentum is such that you slam into the Wartortle, sending it flying through the air, back towards the girl, who smartly leaps out of the way before a loud crash echos through the woods, scattering the nearby pokemon.
"Mikey!" she shouts as she rushes into the dust cloud you'd kicked up with your attack, and soon you can see her knelling beside the Wartortle, who looked too beaten to move, his eyes unfocused as he lay there groaning.
"Grrr, that jerk. Don't worry Mikey, we'll get him," she says as she holds out his ball again, and the pokemon is suffused with light, before seeming to disintegrate, vanishing inside. Turning to face you again she already has another pokeball at the ready and tosses it at you, releasing your next opponent.