Invisible Strangler is a 1984 American horror film directed by John Florea, an alternate cut of the 1978 film The Astral Factor, also known as The Astral Fiend, starring Robert Foxworth, Stefanie Powers, Cesare Danova, Sue Lyon and Elke Sommer. Arthur C. Pierce wrote the screenplay and co-directed the film uncredited.The film was originally released in 1978 as The Astral Factor aka The Astral Fiend. It was later re-edited into a new, shorter version entitled The Invisible Strangler and released on video in 1984. Invisible Strangler runs 85 minutes, about ten minutes shorter than The Astral Fiend, and most of the killer's dialogue lines during the murders were edited out, while new music and some entirely new scenes were added.

The film is available today on DVD as The Astral Fiend, which is the original uncut 1978 version of the film. It is on a double feature dvd with The Brain Machine (1972).