A star with serious compression issues.

Here's the strange part.

A neutron star takes the idea of packing light and does the exact opposite. These stellar remnants can squeeze more mass than the Sun into something roughly city-sized. The familiar billion-ton teaspoon comparison helps convey that density, but it is not a serving suggestion. Scientists still investigate what matter does under such extreme conditions; the analogy is easier than the physics. (NASA Goddard)

Go straight to the receipts.

Curious about the methods, dates or details? Open the original source and keep the caveat in view.