Venom

The Venom symbiote was a symbiote spawned at some point during the reign of the dark elder god Knull. Becoming an outcast of its species, the symbiote was discovered by Kree explorers, who bonded it to a soldier named Tel-Kar to use its disguising abilities to infiltrate the Skrull armada. However, Tel-Kar was forced to separate from it, and after parting ways, it would later bond to an unnamed alien, who used it to commit genocide against his own species. Still desiring to protect its hosts instead as opposed to dominating them, it was imprisoned by its brethren, with this prison being incorporated into the makeup for Battleworld by the Beyonder. Being discovered by Spider-Man during the Secret Wars, it bonded to him and assimilated his powers into its own genome. Unfortunately, it was later discarded by Spider-Man when he learned it was alive and sentient. When Eddie Brock, a journalist who had his career ruined unwittingly due to the actions of Spider-Man, came to Our Lady of Saints Church to commit suicide, the symbiote sensed his anger and bonded to him, forming the super villain Venom. Over time, the symbiote's bloodlust and hunger worsened until it became too much for Eddie to stomach, leading to them parting ways.