What name was used to create a fake that can destoy superman?

The name used to create a fake that can destroy Superman is "Doomsday." In the DC Comics universe, Doomsday is a monstrous creature engineered to be the ultimate weapon against Superman, possessing immense strength and the ability to adapt and survive any form of death. He famously battled Superman in the "Death of Superman" storyline, leading to a climactic confrontation between the two.