Urs Fischer's "Untitled" (2011), a wax sculpture over 20 feet tall, melting on the floor of the Geffen Contemporary at MOCA. Fischer subjects a trio of sculptures -- an office chair, a life-size figure of the Italian painter Rudolf Stingel, and a copy of Giambologna's sixteenth-century marble sculpture "Rape of the Sabine Women" -- to a process of controlled burning, creating a performative installation that changes with every visit, a marriage of the ephemeral and the monolithic.