Carnage is Cletus Kassidy. He is an enemy of Spider-Man.
He is an insane serial killer. When he was in jail, the Venom symbiote split upo into a different symbiote: the Carnage symbiote. The Carnage symbiote made its way to Kassidy's cell and bonded with Kassidy, turning him into the psychotic villain Carnage.
He has the power to mold his limbs into any shape, such as hammers or blade. He has sharp teeth, super-strength, super-speed, invulnerability and a red viney version of Spider-Man's web.