Intruder (2008)

When Andrew and his disturbed girlfriend, Lila, travel to a secluded estate for a weekend getaway, they fall into the clutches of a predatory murderer who stalks the dark forest near the house. On Halloween night, the town of Hobb's Ferry finds itself at the mercy of the Intruder, a bloodthirsty clown, whose depraved tricks push Lila to the brink of madness.

Unfortunately the movie Intruder is not yet available on HBO Max.