An article published in the journal “Nature” describes the discovery of a supernova that seems to have exploded more than once. Called iPTF14hls, it was identified in 2014 by the Intermediate Palomar Transient Factory but in that position a supernova had already been recorded in 1954. It could be the first case discovered of a type of supernova called a pulsational pair-instability supernova, in which a star is so hot and massive that it produces in its core antimatter that causes periodic explosions.