Children learn many useful things from television shows and cartoon characters. They learn letters and numbers from the characters on Sesame Street; Dora the Explorer helps them hone their reasoning and problem-solving skills. Now, a cartoon character is telling them when they should die. He’s a dog in a lab coat named “Professor Schpinkee.” He is a creation of the Australian Broadcasting Corporation’s Planet Slayer website. Kids who visit the website are invited to pay a “game” called “Professor Schpinkee’s Greenhouse Calculator.” But instead of learning letters or numbers—or even how to take a bite out of crime—they learn “how...