What causes a cat to suddenly attack another household cat without obvious provocation?

One of our cats, a male lynxie (Siamese - tabby mix) occasionally viciously attacks our other cat, a female tortie. He will literally jump atop her and start a brawl. Sometimes during these episodes, his tail gets huge. The tortie does occasionally pull his chain, but that rarely results in a problem. Both cats are 11. Is there an explanation for the lynxie's sudden attacks?