Following the language Georges Bataille adopted when studying the ritual traces of animal sacrifice found in Paris’s abattoir at la Villette, this project explores the potential for a formless architecture through the program of an extended museum around Rome’s ex-mattatoio. Entrails of Testaccio articulates an architectural response to an existing program to transform Rome’s neighborhood of Monte Testaccio into an open-air museum. A new path through the existing fabric delineates disparate spaces of repressed desire culminating in a series of architectural events. This proposal encourages Romans to explore and experience the ex-mattatoio in ways appropriate to its original function as a slaughterhouse, extracting formless architectural moments through the lens of carcasses.