  We present an experimental study of the motion of a viscoelastic micellar
material around a moving cylinder, which ranges in response from fluid-like
flow to solid-like tearing and fracture, depending on the cylinder radius and
velocity. The observation of viscoelastic crack propagation driven by the
cylinder indicates an extremely low tear strength, approximately equal to the
steady state surface tension of the fluid. At the highest speeds a driven crack
is observed in front of the cylinder, propagating with a fluctuating speed
equal on average to the cylinder speed, here as low as 5% of the elastic wave
speed in the medium.
