What causes a pulsar to form?
Pulsars are quickly rotating neutron stars — under something like 10 miles in size, rotating with periods less than about 1 second, made up of neutrons (plus some other stuff). A neutron star is apparently the product of a supernova explosion. It’s the leftover core of the star that went supernova. The core collapsed and spun up (like an ice skater pulling her arms in).