Warning! SPOILERS ahead for the ending of Venom!
As the end credits scene of Venom revealed, Woody Harrelson makes a cameo in the film as serial killer Cletus Kasady in a clear set-up for the inclusion of the villainous Carnage in a potential Venom sequel.
Director Ruben Fleischer recently sat down for a one-on-one spoiler chat with IGN wherein he discussed the casting of Harrelson and his reasons for why Carnage wasn’t used as the villain of the first Venom movie.
The mid-credits scene shows Eddie Brock (Tom Hardy) back in action as a working reporter after defeating the Life Foundation. He visits San Quentin State Prison to interview an inmate, an interview requested by the killer himself.
Source: IGN.com Why Carnage Wasn't the Villain of the Venom Movie