What an IZ Is Is Hard to Say, but It's Easy to Say What It Isn't: Quiet - New York Times

The heart - and belly - of iZ is a two-inch speaker that plays audio piped in through a standard jack at the back. When music is playing, iZ responds with synchronized colored lights inside its trumpetlike mouth. Its eyes bounce in their sockets, and it throws in burps and gurgles that may or may not be music commentary.