Interpretation is at the center of psychoanalytic activity. However, interpretation is always challenged by that which is beyond our grasp, the 'dark matter' of our mind, what Bion describes as ' O'. O is one of the most central and difficult concepts in Bion's thought. In this paper, I explain the enigmatic nature of O as a high-dimensional mental space and point to the price one should pay for substituting the pre-symbolic lexicon of the emotion-laden and high-dimensional unconscious for a low-dimensional symbolic representation. This price is reification--objectifying lived experience and draining it of vitality and complexity. In order to address the difficulty of approaching O through symbolization, I introduce the term 'Penultimate Interpretation'--a form of interpretation that seeks 'loopholes' through which the analyst and the analysand may reciprocally save themselves from the curse of reification. Three guidelines for 'Penultimate Interpretation' are proposed and illustrated through an imaginary dialogue.