10 Comic Book Catastrophes That Killed Millions
5. John Stewart Fails To Protect Xanshi - Cosmic Odyssey
Death toll: A whole planet
What's the only thing worse than the destruction of an entire county? Try an entire planet.
John Stewart is one of the better Green Lanterns out there, at least compared to Hal Jordan (who was once corrupted by an evil alien force into going insane and decimating half the galaxy) and his replacement Kyle Rayner (the man for whom the unfortunate concept of 'women in refrigerators' was coined).
Even Stewart dropped the ball every so often, though, with the most damning stain on his permanent space cop record being the time he failed to protect the planet of Xanshi from being devoured by an avatar of the Anti-Life Equation. He was still kind of a rookie, having left Earth to go be a superhero amongst the stars, but that doesn't quite excuse what a !*$% up allowing an entire planet to get destroyed is.
The event, during the 1988 Cosmic Odyssey mini-series, earned him the ire of J'onn J'onzz the Martian Manhunter, and resulted in the creation of the villainess known as Fatality; Stewart was so cut up about his failure he even contemplated suicide.
John got over that in the end, and the other J'onn forgave him, but the Anti-Life Equation still did wipe out an entire planet roughly the size of Earth.