  We study collisions between two strongly interacting atomic Fermi gas clouds.
We observe exotic nonlinear hydrodynamic behavior, distinguished by the
formation of a very sharp and stable density peak as the clouds collide and
subsequent evolution into a box-like shape. We model the nonlinear dynamics of
these collisions using quasi-1D hydrodynamic equations. Our simulations of the
time-dependent density profiles agree very well with the data and provide clear
evidence of shock wave formation in this universal quantum hydrodynamic system.
