New work suggests some massive stars might cut themselves in two using a "relativistic blade"

Under the right condition instead of narrow, polar jets, a blast wave could expand straight outward along the star’s equator, break through the surface, and cleave the dying star clean in two: As a massive star begins its final collapse, its core can transform into an ultra-dense, ultra-magentized, and rapidly rotating neutron star known as a millisecond magnetar. The intense winds and magnetic field surrounding the magnetar would deposit enormous quantities of energy into the area around the core that must escape to the surface. Thanks to the magenetar’s spin, that energy would be concentrated into narrow “lamina,” or blades, of outflowing matter that would propagate outwards in just a few seconds. See also:

Crystallization, Convection, and a Magnetic White Dwarf Mystery