I also worked for a toxic bully manager. He enjoyed making people who showed fear, become terrified. As soon as he thought anyone was intimidated, he would jump in and become aggressive to make it worse.
Because I stood up to him and never showed any weakness when talking to him, he acted like a normal competent manager.
My favourite story about him happened one day when he flew into a rage about nothing in particular with a young secretary, who happened to be in his office. There were witnesses. I was one of them.
She kept calm in front of his tirade and announced,
“I refuse to be treated like this, I resign.”
And she walked quietly out of his office, left the company that very minute, and never came back.
This young secretary changed my toxic bully boss forever. I never saw him shout at anyone ever again. I suspect that the bully in him was so humiliated with witnesses watching his defeat, that he stopped this behaviour.