I also agree with Karen. I was thinking to just make a statement like "well, so-and-so was being his normal self", since you said your manager knows how this guy is. And then if your manager asks for more details give them what you wrote down.

Good luck! This guy should not get away with treating you like this. You are, afterall, the assistant manager. You are in management, and all employees should respect that. They don't have to like it, but they should respect it.