Doomsday vs Our Earth...with a twist!
OK, heres the catch. Doomsday is sent by The Presence to kill every sentient being on our Earth, but he is only given 11 hours to do it. He has to destroy every last living being. There must be NO SURVIVORS!!!!
Edit-
He cannot lay waste to the planet itself. He has to find every living being and kill them as mandated by The Presence. If he doesn't succeed, he will be wiped from existence. The Earth must be cleansed, it is far too corrupt.