Black holes don't always destroy the stars they feed on, however. Even though they don't suck anything up, black holes can act like cosmic vampires in another way: If a black hole is in a binary system with a star, its gravity can pull stellar material from the star's outer layers, keeping its stellar victim alive while gradually feeding on it. This process hastens the demise of the victim star, which itself could leave behind a second black hole in the system when it eventually dies.