Michael is convinced Mr. F is the name of a spy working against the Bluths, but M R F actually stands for "mentally retarded female," i.e. what Michael's new girlfriend Rita (played by Charlize Theron) is, unbeknownst to him. This gag was, admittedly, made quite memorable by its Bond-esque theme music, which cooed "Mr. F" (a play on Dr. No). Mr. F was first believed to be Rita, then Tobias (Mr. Funke?), who was, unbeknownst to even himself, working as a mole for the FBI. Michael, too, is in the dark; no longer thinking Rita is a spy, he asks her to marry him. He doesn't learn what she really is until shortly before their wedding.