It's Alive | 1973
Frank and Lenore are looking forward to the birth of their second child. But when the baby is born, it is a monstrosity with claws and fangs. When one of the doctors tries to suffocate the freakish child, it kills him, along with the rest of the staff in the room. This is just the beginning of a string of murders by the vicious newborn, who is eventually being hunted by almost everyone, and protected only by its mother.