One of my all time favorites.

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."

Excellent and certainly provocative... If nothing else, the film is a real conversation starter.