I know many will start to say it's kind of abnormal or start talking about spiritual things, but one thing that is sure here is that there is certainly an explanation for this.
According to healthline, some babies are usually born with one or more teeth which are called Natal teeth. Natal teeth are usually rare, they occur in about 1 out of every 2,000 births.
It can really be a shock to see a newborn baby with teeth but you don't necessarily need to worry or take any action unless it interfere with feeding.
To know more about Natal teeth, causes, types and their rsik factors, you can read more here