Scanning through data fresh off the telescope, we saw two ghosts dancing deep in the cosmos. We had never seen anything like it before, and we had no idea what they were. Several weeks later, we had figured out we were seeing two radio galaxies, about a billion light years away. In the centre of each one is a supermassive black hole, squirting out jets of electrons that are bent into grotesque shapes by an intergalactic wind. The two galaxies we think are responsible for the streams of electrons (shown as curved arrows) that form the Dancing Ghosts. But we don’t understand what is causing the filament labelled as 3.