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I understand that the Briefcase is just a Mcguffin, but I read a long time ago a theory which involved the briefcase containing the stolen soul of Marsellus Wallace. I know this supposedly played into the number "666" and the Band-aid on the back of his head, and the repetition at the end of the film as well as the repeated bible quotation. could anyone expand of this?
Also Are there any other theories that I am not aware of in relation to the briefcase, or the film in general?