Stacy (the Japanese zombie flick)

My husband and I just got done watching Stacy, a bizarre little movie about Japanese schoolgirl zombies. I liked it, hubby didn’t.

I’m posting this in the hopes that some other dopers have seen this. For those who have, a question.

You know the bit at the end, when Eiko has her monologue about identical twin sisters playing catch, but it looks like killing each other? What the hell was that about? I pretty much get the rest of the movie, but I can’t figure out what that had to do with anything else in the movie.

If anyone can give me a clue, I’d be ever so grateful.