Something strange is afoot in the galaxy known as 1ES 1927+654: In late 2017, and for reasons that scientists couldn't explain, the supermassive black hole sitting at the heart of this galaxy underwent a massive identity crisis. Over a span of months, the already-bright object, which is so luminous that it belongs to a class of black holes known as active galactic nuclei (AGN), suddenly grew a lot brighter—glowing nearly 100 times more than normal in visible light.
