"Day 18 - Your favorite foreign horror film (outside of your country of origin)"
I don't understand the little footnote thing cause if you are in your country of orgin, it wouldn't be a foreign film, would it? Or maybe they meant nationality wise? Like I can't pick a movie from Ireland, Poland, or Spain/Mexico (That gets a little confusing) or what? Well, fuck it, I'm picking a French movie anyway and I'm gonna go with "High Tension".
(There were a lot I almost put here. I didn't think I watched that many foreign films. Take that, Dylan!)
"High Tension" was directed (maybe written?) by Alexander Aja, who's a hardcore guy. The film is about a girl named Alex visiting her friend and the friend's family for a weekend. At night, a creepy truck pulls up and a shadowy guy comes out and starts killing the family and he kidnaps the friend. Alex hides on the truck, trying to free the friend.
I'll stop there cause everything after that falls into spoiler territory. The ending, if you think about it TOO much, will make you go "Wait...what?" but try not to think about it too hard and just enjoy the ride.