A brilliant film that helped define a genre

The film makes a home in your brain and the only cure is to see it again.

A film with more than the usual spoiler issues. Talking about it in any detail feels akin to handing you a gift-wrapped present and saying, "I hope you like it -- It's a thriller about a diabolical secret experiment."

Exactly the movie you think it is, but not the movie you want it to be.