"Eddie Brock, a disgruntled ex-journalist, and Spider-Man's jilted alien symbiote costume that he acquired in Secret Wars, became Venom, perhaps the most successful iteration of "evil version of the hero" in all of comics. He wages a campaign of torment against Peter Parker, invading his private life and threatening his loved ones. He is not altogether evil, though: he exhibits moments of compassion, like rescuing a little girl during a pitched battle with Spider-Man. He even ends up in a few Enemy Mine situations with him - generally to combat the symbiote's "child", Carnage, which has bonded with Serial Killer Cletus Kasady."