Directed by: Charles E. Sellier Jr.
Starring: Gilmer McCormick, Lilyan Chauvin, Robert Brian Wilson, Toni Nero
Revealing mistake: When Billy smashes through the door of Linnea Quigley's house it's obviously made of cardboard.
Revealing mistake: The sheets tying Billy's wrists to the bed aren't tight enough to keep him bound.
Revealing mistake: The robber who kills Billy's mother is shown cutting her throat but with the flat side of the blade. Moreover real blood doesn't ooze out so thickly, indicating it was makeup.
Character mistake: Andy speaks of Billy changing in the two months after he was hired when he was hired in the spring months ago.
Billy Chapman: Mommy, you shouldn't have said that. It's naughty to say bad things about old people. Santa Claus will punish you.
Trivia: This first came out in theatres on the exact same day as another beloved slasher film classic: the original "A Nightmare on Elm Street."
Answer: Dementia, Alzheimers, mini strokes to the brain. Take your pick.