This morning, I asked, "What's the matter with you?" He responded, "What's the matter with YOU?" In the car I told him that God and Santa are watching and neither one is pleased with his behavior. I then told him that I could get in touch with Santa and see to it that he got no presents this year. That shut his mouth. He will be in his room after school.
There is no point in asking a 6 year old questions like that. They can't answer them. Many adults can't answer them. Stop focusing on Santa, and start focusing on talking to your child in a calm way to try to find out what the problem is.