If you associate pentagrams with evil or Satan, then in your dream it may mean you are having a bad feeling about someone or something in waking life. Ask yourself what is the biggest negative influence in your life right now. Your dream may be trying to address that issue and is warning you that it is time to correct what is wrong or move on from what is causing the negativity. Pentagrams are often believed to protect against evil so you may be having a gut feeling in real life right now that you need to get out of a bad situation.
A pentagram also has five points so it may be connected to the number 5 or the amount of 5 in your life. So put on your thinking cap and see if the number 5 or the amount of 5 has significance in your life right now.
In tarot the pentagram is a common spread for the cards. Your dream may be telling you it’s time to think about your future and plan for it.