Source: Elseworlds 80-Page Giant #1 (1999)
Type: ElseworldsWhat if Kal-El's rocket crashed in Crime Alley, killing the Waynes instantly? Simple. Young Bruce survives, but is horribly disfigured and swears vengeance on the infant from another planet picked up by multi-millionaire Lex Luthor. Baby Kal-El, raised by Luthor, becomes a gun-toting corporate lackey, while Bruce becomes Batman and gets his hands on the only pieces of kryptonite not disposed of by Luthor. They meet. Bang bang. And Batman uses the last bullet to send himself to his parents.
Voila. World's Deadest. It's obvious, really.
I imagine this Earth also features Abin Sur crashing into Barry Allen's lab, Oliver Queen getting stranded on Paradise Island, and Baby Arthur raised by Dr. Erdel.