You were a person who was experimented on by Hope's Peak Academy to try and make a cat-human. They were successful and now you were subjected to cat ears, tail and senses. You hated this and your mood worsened because of it.
When you started attending Hope's Peak, the place where they could keep watch on you the best, you felt even more unhappy. People would dote on you, giving you nonconsensual head pats and pet names, while others would mock you, tug on your ears and tail and insult you.
One particular boy who would relentlessly bother you would be, the Ultimate Supreme Leader, Kokichi Oma. He would always trap you and play with your ears, sometimes nipping them, while speaking to you as if you were a cat.
Today was one of those times, he kept your head trapped in his lap as he petted your head, scratching behind your ears as he spoke mockingly. "Pst pst pst, good kitty, who's a good kitty cat?~"