Sun-Eater

Sun-Eater

A powerful amophous cloud-like entity that can consume entire star systems, and even galaxies of stars. Wandering through space in the 30th century, it is historically responsible for the extinction of many suns -- and then, it sets its sights on the Milky Way and the earth's sun. The Legion of Super-Heroes sets out to confront the menace, but because many members are off on another mission, the Legion is forced to call on the help of the super-criminal organization known as the Fatal Five. (Adv No. 352, Jan 1967: "The Fatal Five!")

After a failed attempt to divide the Sun-Eater into smaller pieces by the heroes (because the Sun-Eater has consumed many red suns, even Superboy is weakened by it) and villains, the entity is finally destroyed by a bomb made of Absorbium -- but at the cost of Ferro Lad's life. (Adv. No 353, Feb 1967: "The Doomed Legionaire!")

Apparently, a Sun-Eater is a weapon created by a powerful race of beings known as Controllers.