Madman

Madman is a 1981 American slasher film written and directed by Joe Giannone and starring Gaylen Ross and Paul Ehlers. The plot focuses on an axe-wielding murderer named Madman Marz who, after accidentally being summoned by a group of campers during a campfire tale, begins to stalk and murder the young adults.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.