Captain America Comics #37

Cap and Bucky encounter the Nazi Dr. Agony who, along with his hypnotic black panther Tula, is attempting to develop a serum which will make men immune to pain. Tula's hypnotic purring holds Cap and Bucky in its thrall until Cap manages to step on the panther's tail. When Cap turns on the lights, the panther is blinded in its leap and lands on Dr. Agony. Dr. Agony stabs the panther to death while it tears his throat out.