“In the movie, this young guy is giving it as a gift is a strange thing. The vibe in the movie is strange, too, with him saying it’s symbolic. I can’t let anyone unfamiliar with scholar’s rocks pass it over, I have to create that odd mood. For actors and directors, I think that’s a big feat. [Laughs] Even though I’m the one who said it, I know it sounds weird. But, for foreigners seeing this stuff, thinking, “That’s weird, why is that in there? Does that have to be there? Is it a symbol?” Well, the actor outright says it’s a symbol, so it’s even weirder. “So maybe it’s not a symbol?”
In the beginning, it’s supposedly metaphorical, and by the end, it’s a literal weapon used to smash in somebody’s head. I think the rock brings an extra layer to the story. It feels like this cursed object and ends up being covered in blood. It tells the whole story of all these horrible events. I don’t remember why I thought of it at first, but that’s how it ended up.”
— Bong Joon Ho