On 15 April 2020, space-based gamma ray detectors recorded one of the most elusive events in astronomy—a giant flare erupting from a magnetar, a highly magnetized neutron star, in a neighboring galaxy. Over previous decades only three magnetar giant flares have been confirmed, and the road to understanding them has paralleled the study of magnetars themselves. In 1979, the first giant flare arrived at the dawn of gamma ray astronomy. U.S., European, and Soviet teams, in a rare case of Cold War–era collaboration, recognized it was from a source unknown to science. But it wasn't until 1992 that scientists postulated a possible cause: a starquake rearranging the surface of a neutron star 1 trillion times more magnetized than a refrigerator magnet. Since then, magnetars have been invoked again and again as the possible engine behind several types of unexplained astrophysical explosions. The 2020 giant flare, studied in greater detail than ever before, supports several aspects of the starquake model—and suggests both magnetars and their rare quakes are still common enough to be linked to many other transient events seen in the more distant universe.