A favorite of late night TV in the 60's and 70's, this film was usually referred to by LA Horror Host "Seymour" (Larry Vincent), as "The Attack of the Bunny Slippers", because of the cheesy monsters.
Producer Ed Nelson, who also stars, created the parasites himself using little wind-up toys covered with fur from an old coat and pipe cleaners for antennae.
Some sources have claimed that future exploitation director Jack Hill acted in this film. "Jack Hill" was actually the name being used by veteran actor Cornelius Keefe (who plays Senator Walter K. Powers) for his film credits during the 1950s.
The producers of this movie were sued by Robert A. Heinlein, who claimed the plot stole several elements of his novel, "The Puppet Masters". The suit was settled out of court.
To save money on his own film, Ed Nelson, who also produced, wears the same coat he used in Night of the Blood Beast.