Season 1 & 2 Edit
V-252, formally known as Venom, is a symbiote from the Klyntar race which NASA had discovered while in space. At first, no one thought it was actually alive until Spider-Man found it was bonded to him and wouldn't come off so easily. Later he finds out its main weakness is sonic blasts or just loud sounds in general.
In Season 2, while Eddie Brock is taking pictures of the V-252, it breaks the glass of its container and soon makes Eddie its new host.
Three years before Peter Parker became Spider-Man, NASA donated a substance they discovered to Horizon High for further study, and Max Modell named it V-252 . When Peter, Miles, Gwen, and Anya were helping stabilize it, the V-252 bonded with its first host, Peter Parker. After he rejected it though, the substance bonded with "King of the Football Field" (Flash Thompson) and became Venom.