"How Can an Immortal Die?" Guest-starring Black Canary. A wounded Katma Tui comes to Earth, summons Green Lantern for a mission in space in which the Guardians of the Universe are in danger. Guest starring Black Canary and The Mocker. Script by Denny O'Neil, pencils by Mike Grell, inks by Vince Colletta. Cover by Grell. Cover price $0.35.