My son hates the potty

All of a sudden my almost 2 year old son is kicking and screaming anytime we try to get him on the potty. He didn’t used to act this way. I have tried rewards but then he just screams more because he wants what i have but doesn’t want to sit on the potty to get it. He is not completely potty trained but usually will poop on the potty 80% of the time. Which has now been put on hold because of this tantrum scene.

What can i do to stop this madness?! 😭