TRILOGY OF TERROR, even though I acknowledge that it's not an especially good movie. The film's following is based on two things: the performance of Karen Black, and the presence of the "Zuni Fetish Warrior" doll in the TV movie's final chapter.
According to the March 1, 1975, issue of TV Guide, director Dan Curtis spent a tidy sum on the "Zuni Fetish Warrior." There were three versions of the doll Ugly, Uglier, and Ugliest. The motorized version able to "run" in the film's distance shots cost about $15,000 to create, which is about $65,000 today when adjusted for inflation. You can get a look at the variations in the character in the TV Guide ad at the bottom of this post.
The doll was the work of designer Erik von Buelow, who has all of three production credits to his name (the others are EMPIRE OF THE ANTS and THE FOOD OF THE GODS). While Curtis certainly got his moneys worth from Von Buelow's creation, the doll's aftermarket value wasn't great. It was sold to a private collection through a 1991 auction for a modest $4,400.