Walter Dixon

He is the original writer of the Hell Riser 2 movie, but it was changed by the studio. His script was originally called Lord of Death (or something like that). Because of his contract, he is allowed on set.

Background
He is the original writer, but because it was changed so much, it wasn't his story anymore. He is seen breifly around set, and Sam and Dean notice him, but they think hes a PA. They find out that his script was like a How To Summon spirit manual.

Back on set, Walter takes his anger out on the guy who rewrote the script, and summons spirits to kill for him. Sam and Dean try to stop him. So Dean watches the guy and Sam goes after Walter. He tries to stop Walter, but is too late. Walter smashes the Taliman he had to control the ghosts without realizing what he done. The ghosts get their revenge on Walter as they shred him to death.