I had a giant tabby cat that chased a black lab in front of a truck and killed it. I also had a much smaller fluffy orange kitty that used to attack cats twice it's size. He'd come inside covered in cuts and we'd think he was being bullied. Then one day I watched him fight with another cat, and when the other cat tried to get away my cat just went after him. This other cat was huge.

All this is besides the normal things, like the retardation surrounding laser pointers.