A shapeshifting villain/anti-hero from the Spider-Man series of comic books published by Marvel.
Venom is an alien symbiote that initially attaches itself to Peter Parker, leading to the creation of the Symbiote Suit (or the black Spider-Man suit). However, the power boost granted by the alien entity proves to corrupt Peter's mind, and he rids himself of it - leading the scorned creature to take over Parker's rival, Eddie Brock, and swear revenge, eventually settling into the role of an anti-hero.
