Katsuki got hit pretty well with a de-aging quirk which sent him back to being a little short tempered kid again. Which he seems to be sent back at seven years old. And you were choosed to take care of him, which is a painful mess. He's completely destructive and rarely calm.

Bakugou grabbed a vase and getting ready to throw it. Before you stopped him. "Get your hands off! It's mine! I can break it whenever I want!" He said pouting at you. Like a complete child.