The Strangers

The 2008 (but filmed in 2007) debut movie of filmmaker Bryan Bertino. The movie is about a couple, Kristen McKay (Liv Tyler) and James Hoyt (Scott Speedman) being ambushed in James' family's vacation house by mysterious strangers apparently For the Evulz.

A sequel was stuck in Development Hell for a decade; The Strangers: Prey at Night was finally released in 2018.

Not to be confused with the 2006 horror film Ils (aka Them), which has a similar premise.

Tropes used in The Strangers include:

Accidental Murder: James accidentally shoots Mike.
Bolivian Army Ending
Car Fu
Danger Takes a Backseat: One of the most contrived uses of all time.
Developing Doomed Characters: The first twenty-thirty minutes of the movie.
The Faceless: The killers.
The Family That Slays Together: The three masked people, presumably.
Follow the Leader: Arguably in the mold of Ils and Vacancy
- The Onion's AV Club described it as "Funny Games without the scolding."
For the Evulz: The killers' motive (and the movie's tagline) is Because You Were Home.
How We Got Here: The movie begins with the end and then rewinds.
Malevolent Masked People: The Strangers.
Men Are the Expendable Gender: of the two main characters, only the female one gets to live to the end of the movie, even though it defies everything the movie set up before.
No Name Given: The Strangers are credited as "Doll Face", "The Masked Man", and "Pin-Up Girl", but none of those names are heard in the film.
Nothing Is Scarier: This was the main source of the scares in the movie. How effective the scares are depends on the viewer (see YMMV).
Not Quite Dead: Kristen
Offscreen Teleportation: The Strangers are adepts at this.
Red Herring: The smoke detector. When Kristen takes it off of the ceiling early on and leaves it lying on the floor, it seems like a foregone conclusion that the strangers will later try to burn the house down. They don't.
Too Dumb to Live: All the good guys. Kristen just runs around the house terrified and manages to injure herself, James manages to tell his girlfriend to stay in the middle of danger while he goes looking for help, and their friend Mike, despite the various things suggesting foul play (including a rock thrown on his windshield) does not think for one second about calling the police or even calling for his friends which leads to Accidental Murder.
The Un-Reveal: The Strangers at the end take off their masks but the movie cuts away before you can see their faces.
Very Loosely Based on a True Story: Director Bryan Bertino recounted a story from his childhood when a stranger came to his house at night, asking for a woman that wasn't there. The next morning, it turned out that the houses that didn't answer the door had been broken into.
- He also said that he was inspired by a 1981 homicide where a woman, her two children, and a third child were murdered in their rural home in the Sierras, which turned up absolutely zero suspects.