The Rise and Fall of Ziggy Stardust & the Spiders from Mars… So let’s see. An alien descends from the heavens in the waning days of life on Earth. His glittering purpose is to inspire hope and peace despite the dire days ahead. He adopts the guise of a rock & roll star, perhaps suspecting that this is the best way to reach and convert mankind. Things go awry, and the messiah (the Messiah?) is dragged into a downward spiraling pit of lecherous excess and ego. Presumably, the world explodes shortly thereafter.
If you’ve mastered interstellar travel, there are probably better things to do than visit Earth.