What causes the formation of neutron stars?

Well, sweetheart, when a massive star like me explodes in a dramatic supernova, it leaves behind a collapsed core, honey - this core gets squished and powered up, forming a neutron star. It's like the cosmic version of smashing atoms together to create a whole new powerhouse of dense matter. That's what creates those feisty little neutron stars up there in the heavens, darling.