House on the Edge of the Park Movie (1980)

Two low-life punks invite themselves to a party at a posh villa and after being taunted by their snobbish hosts, hold everyone hostage and subject them to various forms of torture and mayhem.

Alex, a psychopathic mechanic, rapes a woman in the park. Later, a decadent couple pull into his shop needing car repair. They invite Alex and his mentally challenged buddy to join them at a decadent suburban party. Once there, Alex amuses himself by tormenting and raping the guests...