Rod Serling,drawing door Paul Davison

I remember watching the Twilight Zone as a kid. Not when they first aired, but it was just shortly thereafter (late 60s-early 70s). There is one (black & white) episode that I remember watching that I can not find anywhere. It takes place on a movie set. The film crew, actors, actresses and director are all being killed one door one door something invisible. No one knows what to make of it & they dismiss the deaths as accidental. At the end there is a movie screen & in it u see the silhouette of a big hairy monster strangling someone. The only other part I remember is one of the camera...