  We investigate the collapse dynamics of a dipolar condensate of 52Cr atoms
when the s-wave scattering length characterizing the contact interaction is
reduced below a critical value. A complex dynamics, involving an anisotropic,
d-wave symmetric explosion of the condensate, is observed. The atom number
decreases abruptly during the collapse. We find good agreement between our
experimental results and those of a numerical simulation of the
three-dimensional Gross-Pitaevskii equation, including contact and dipolar
interactions as well as three-body losses. The simulation indicates that the
collapse induces the formation of two vortex rings with opposite circulations.
