Weirdest film you've ever watched and liked

I've seen a lot of movies and I've seen a lot of weird stuff, most of them is worth one watch, some are not worth it at all. But I can name a few weird movies that I liked and actually favorited. One is "Old Boy". I liked it because of it's storyline and twist.
WAIT! IF YOU CLICK THE LINK IT'S A SPOILER. LOL

What about you? Have you seen a weird movie and liked it?