Frankie had done what came naturally when the big human had suddenly appeared and tried to grab him. One hundred million year old instincts took control and Frankie lashed out with the huge claws on his feet, opening the human up even easier than the thick skinned prey of old. He knew he didn't need to eat, but the rage was on him, and so he bit and tore.
Suddenly he felt his owners fear. That wasn't right. She petted him and let him run free when she could. He ran back, to find owner struggling against another big man.