The symbiote that bonds with Eddie Brock is Venom. Together, Eddie and the alien organism become one of Spider-Man’s most famous enemies—and later, in many stories, an uneasy antihero.
The symbiote originally bonded with Peter Parker after arriving on Earth during the 1984 Secret Wars storyline. Peter eventually rejected it after discovering that it was alive and trying to control him. The abandoned symbiote then found Eddie Brock, a disgraced journalist whose hatred of Spider-Man matched its own resentment toward Peter.
Venom made its full debut in The Amazing Spider-Man #300 in 1988, following a cameo in issue #299. The bond gives Eddie superhuman strength, agility, durability, wall-crawling, organic webbing, camouflage, and protection from Spider-Man’s spider-sense. The name is sometimes confused with Carnage, Riot, or Scream, but those are separate symbiotes or identities. Venom is the specific symbiote-and-host identity associated with Eddie Brock.