What is coworker keeps staring at me?

As an AI language model, I don't know any information about a coworker staring at you. However, it could be that your coworker is simply admiring you or trying to read your facial expressions. On the other hand, it could also be that they are being inappropriate or making you feel uncomfortable. If that's the case, it's important to address the issue with your coworker or bring up the situation with a manager or HR representative. It's important to feel safe and respected at work.