In the violent heart of a dying star, the universe's most elusive particles do not simply flee — they transform, cycling through identities as they carry away nearly all the energy of a supernova explosion. This phenomenon, known as flavor oscillation, has long been understood in calmer cosmic settings, but inside a collapsing stellar core the physics becomes extreme, consequential, and revelatory. Scientists are now working to decode what these shifting particles tell us about the fundamental architecture of matter, using Earth's most sensitive detectors to prepare for the next great stellar