The Manitou is a 1978 American supernatural body horror film produced and directed by William Girdler, and starring Tony Curtis, Michael Ansara, and Susan Strasberg.

It follows a woman in San Francisco who begins developing a fast-growing tumor on the back of her neck which is discovered to be supernatural in origin.

It is based on the 1976 novel of the same name by Graham Masterton, which was inspired by the concept of manitou in Native American theology, believed to be a spiritual and fundamental life force by members of the Algonquian peoples.

She seeks the comfort of an old friend and ex-employer named Harry Erskine, a fortune teller who preys on the gullible to make a living.

Convinced that Karen is being afflicted by black magic, Harry consults a former psychic named Amelia Caruso and her partner, MacArthur.

Unable to help them directly, he advises them that they should seek the council of the vestigial Indian medicine men now surviving in the remote parts.

Harry visits John Singing Rock, (Michael Ansara) a medicine man who tells him about manitou, spirits who exist in everything surrounding them.

Harry and John reach the hospital and draw a circle of sand around Karen's bed in order to limit the spirit using her body.

In another encounter, Misquamacus summons an ancient Indian demon by the name of the Lizard of the Tree while managing to erase the sand circle to harm Dr. Hughes.

After Harry takes Hughes to the lower levels to treat his wounds, he returns to find the entire floor covered in ice; the receptionist is frozen solid.

As they are discussing the plan, the entire room shakes with a violent earthquake, which John reveals as the coming of the Great Old One, a powerful demon, through a portal opened by Misquamacus.