The Mephistophone is an artificially-intelligent musical apparatus that listens to its acoustic environment, changing the shape of its latex surface in response to the features of the sounds that it hears. An early version appeared on-stage in a key scene of Matthew Herbert's chamber opera The Crackle, staged in the Royal Opera House Covent Garden in May 2014. In this first deployment, Matthew applied the device as a "Remembering Table" that reconstructed his interpretation of an abstract audio soundscape of water sounds. Within his interpretation of the Faust legend, the Remembering Table became one element of a Mephistophelean bargain struck be a school music teacher who accepted the promise of technology to fund and transform his classroom. As the members of the Covent Garden Youth Chorus sing of their resulting anxiety, the Table appears as if possessed by an organic and animate entity that dramatically conveys the mystery of music-making machines.