My boss decided to cut my salary out of nowhere, decided to offer 20/hr until he finds my replacement

Could this be him trying to evade taxes? There was no reasoning for this, he doesn’t want me to step down but he cut my wages. It’s a confusing time for me and I’m looking to talk to him Monday to try to stand up for myself. I was already underpaid, and am looking for other means of employment but I want to speak my mind. I will not quit, he has to fire me if he wants me gone. I feel like this move was to get me to quit. Any advice welcome