A new supernova is more than twice as luminous as any seen before, at its peak being brighter than 570 billion suns. Subo Dong of Peking University in Beijing, China, and colleagues found the supernova – dubbed ASASSN-15lh – at a redshift of 0.2326, apparently in a luminous galaxy with little star formation. The power it has radiated in the first four months post-detection strains conventional models for its power source, so in addition to breaking a record, it poses an astrophysical puzzle.