Could your screech have sounded in any way like another male cat challenging him? (reaching here!) Especially if there are any females in heat anywhere near your house. Even fixed males can get a little agitated during that time. Mine sure does...
My cat has attacked me a couple of times when he smelled another cat on me (I pet the feral cats in my front yard) and I honestly think he thought my arm WAS the other cat. I am careful to wash my hands right away if I have another strange animal scent on me.
Another time, he freaked out and attacked my son and then me, when the vacuum made a horrible grinding noise, just as he saw a quilt on the floor that had an animal print.. I think he thought it was attacking him...
How is he now? I would not pet him or touch him for at least two or three days. It is kind of a punishment and it is also a way to let him calm down. It can sometimes take a cat a few days to un-spook.