According to NASA, the U Camelopardalis (U Cam) star is on its death bed. As it begins to run out of fuel and die, U Cam lets out a spherical clouds of gas that circles around its core every few thousand years. The Hubble telescope was able to capture one such blast.
NASA says that when most stars die the shell of gas is usually "irregular and unstable," but as you can tell from the above image, "the shell of gas expelled from U Cam is almost perfectly spherical."
Head to NASA to see the full-sized image.