  We discuss a mechanism by which a giant star can expel its envelope in an
outburst, leaving its core exposed. The outburst is powered by rotational
kinetic energy of the core, transferred to the envelope via the twisting of
magnetic fields. We show that, if the core is magnetized, and if it has
sufficient angular momentum, this mechanism may be triggered at the end of the
asymptotic giant branch phase, and drive a proto-planetary nebula (pPN)
outflow. This explosion of magnetic energy self-consistently explains some of
the asymmetries and dynamics of pPNe.
