Doomsday

The creature was unleashed onto Krypton, only to be repelled by Colonel Zod using an ancient Kryptonian warsuit (though Zod later hinted that he created the creature himself to serve as a rallying point to a pacifistic and 'soft' Krypton). Decades later, the creature would come to Earth, where it would find Superman. Little is known of their confrontation: what is certain is that Doomsday's arrival was heralded by the sky burning red, and when it appeared, it killed Superman and destroyed Metropolis, a day that would be known forever after as 'Doomsday', giving the monster a name.