Sun-Eaters

The Sun-Eaters are an extraterrestrial species of powerful creatures that feeds of the energy of small stars, thus making them a sort of living bombs.

Overview
A baby Sun-Eater was found by Superman during one of his adventures, and eventually he choose to keep it as a pet in the Fortress of Solitude.

Behind the scenes

 * In the DC comics, the Sun-Eaters were created by an alien race known as the Controllers as a way to destroy entire worlds that they deemed to be too "evil."