Thanks for your response. However, I tried to make it clear that we had just seen a temper tantrum and this was something else. My description of this behaviour was not exagerated. It was extreme and frightening. His sister would have been in serious danger had we not been there to protect her.
His mother and sister, my wife and I were the only people in the room. The situation was calm and loving with attention focused on the children.
I think a temper tantrum is typically characterized as a rejection behavior. That is, the child refuses to interact, pulls away from you when you try to calm or comfort. This was opposite, he was trying, as hard as he could, in any way he could, to hurt any and all of us. He continued until he was too tired to continue.
I am 70, my wife is 46, mother of two, I parented them from infant/toddler stage, neither of us had ever seen anything like this.
He is usually very glad to see me in particular, He comes running, arms up and is content to sit quietly in my lap. Both children and just gotten up from naps so he had just had a bottle and was not hungry. They were in a room with toys, no strangers, plenty of attention available. No sibling quarreling. This event seemed to erupt out of nothing and lasted much longer than the previous tantrum.
Please, we know tantrums, this was much more. I checked with his day care and they had not seen this from him or other children. My wife aggrees that "Berserker" is an appropriate term to characterize the behaviour. Please think beyond tantrum.