(WARNING: LONG CAPTION AHEAD)
He didn’t have time to think. He hadn’t anticipated for this trainer to be so strong. Mewtwo, the legendary Pokémon, had been severely damaged by a human. A human child, no less. Before he had time to even react to the child’s power, the quiet trainer had pulled out an odd-looking Pokéball; purple and pink with a white “M” plastered on the front. Mewtwo attempted to recall a Pokéball like that, but in the short time he did the ball in the trainer’s hand had suddenly started hurling towards him. The clone tried to stop it with his powers, but he discovered he was too injured to even consider the possibility. The ball hit him dead center in his forehead in an instant. For a moment, all he saw was a flash of red.
When his vision returned, Mewtwo rubbed his aching forehead and looked at the trainer before him, standing alone quietly. The clone was seemingly much smaller, as he was looking up from what looked like the glittering floor of the cave. Everything in his field of vision was tinted purple, except for a large white “M” in the center. Tense, the powerful Pokémon quickly looked around and found himself in a sphere shape with patterns identical to those of the ball he had been hit with.
He was inside the Pokéball.
Placing his hands on the sides of his spherical prison, Mewtwo used all of his physical strength to shake himself back and forth to try and break the Pokéball open. When that failed, he pushed on the inside of the button meant to hit the Pokémon, but to no avail. He was trapped in the small space, caught by this monstrously powerful human. He didn’t intend on staying that way, however. Mewtwo mustered every bit of strength he had left and used Psychic to push the button on the strong Pokéball from the outside, right as the trainer was about to pick it up.
White flashed before his eyes as he escaped from the ball. Quickly, he grabbed the ball, released himself, and caused the trainer to fall asleep in an instant. After that, Mewtwo pressed his back up against the wall and slid down, breathing heavily and assessing the situation. He looked at the Pokéball in his hand, thinking about something strange from his short yet frightening time inside of it. The small, inescapable space had somehow made him feel something the legendary Pokémon hadn’t felt in… Well, ever.
Tension. Panic. Shock. Pressure.
Fear.
True, utter fear.
For context: This is from BEFORE Mewtwo and Lucario met for the first time and before he got all of his current scars and burns. This is one of his first training battles, and he went in completely unprepared for the trainer he faced. Bonus points if you guess who the trainer is :>