Humans will stop at nothing to get something that will give them more power. I, of all Pokémon, know this the best. I secluded myself in this cave, surrounded by strong Pokémon. Even if a trainer came in here, the Pokémon would surely stop them. Or so I had thought.

Here stood a lone trainer, a boy. His Pokémon, a simple Pikachu, sprang forward eagerly, but he gave it no commands. Instead, he produced a small, purple orb with pinkish-purple lumps on top. It appeared to be some sort of pokeball. There was an "M" on it. What it stood for, I did not know.
He threw the ball at me, and I was enveloped in its light. I felt a sharp pain in the back of my skull. Something had been injected into me. I didn't even feel like trying to escape the ball at the time. I let him capture me.

Whatever had been done to me spread quickly, and I obeyed the trainer's orders without question. This went on for seemingly years, until I had nearly forgotten I had been from the wild at some point. I had almost believed that I had been with this child my entire life. But the trainer confronted me one day.

"Mewtwo," He started. "I shouldn't have done that to you. To anything. I'm letting you go."

That was all he said. He crushed the ball beneath his shoe, and at once I felt relieved of its power. He had released his hold on me. I was free to leave him. I would have asked him why he did what he did, but the trainer was gone when I looked up again. I suppose he flew away on a bird Pokémon.

To this day, no other trainers have entered my cave. And I have never seen another ball like the ball with the "M" that enslaved me so many years ago.