Action Comics #410

In "The Satanic Son of Superman," Clark Kent, having married the mysterious Krysalla and abandoned his secret identity to be present for their son, faces a terrifying truth after her death: she was a witch, and their child may be destined for darkness. Unbeknownst to Clark, Krysalla gave birth to twins—one bound to the mortal world, the other a malevolent force in a parallel dimension, able to cross over only when his brother lies unconscious.