What is a pulsar?

A pulsar is a neutron star.But, it is a neutron star that is behaving in a particular way.

Note that if there was a neutron star somewhere nearby, say the distance to the closest visible star, which is approximately 4 light years away from us here on Earth, it is just a 1.4 solar mass ball that is 10 miles in radius and does not shine or anything like that. i.e. we would not “see” it. It would just be a dark ball way out in space that we would have no chance of seeing even with the most powerful telescopes.

On the other hand we can and do “see” pulsars that are thousands of light years away from the Earth. So, how are we able to see pulsars, which actually are neutron stars.
i.e. what is a neutron star “doing” that makes it a “pulsar” that we can “see”?