My son is being a little brat at daycare

I spoke to his teacher about the bruise and seems he's being a little brat. She says he and another little boy are being mean to the other kids. Putting him in the corner doesn't seem to work. Lol I'm not surprised there my son never been in the corner in his life's gets his butt whooped at home. I think she's kind of glad he turns 3 at the end the month and will be out of her class