Walburga was terrified. Sirius had never seen anything like it. Never in his life had he seen his mother show any kind of fear. But her eyes were wild and bright with it; like a fever, the fear shined in her eyes and made them over-luminous. She screamed as the wolf knocked her down, and once the wolf was circling her again, both hands moved feebly against the dank, dirt covered stone.
Sirius again couldn't stop the grin as the wolf nipped at her shoulder, then at her hand. She waved her uninjured hand around, trying to bat at the wolf, while her leg, shoulder, and sliced hand all bled profusely. She kicked with her whole leg and screamed bloody murder, waving and thrashing what she could. Sirius watched the pool of blood spread out, black against the filth beneath her. That was the last of her pure blood, he mused internally. Externally, he spoke. "Don't kill her. Mind the arteries, please. She's no good to me dead."