We report the discovery of a planet-mass companion to the microlens OGLE-2016-BLG-0263L. Unlike most lowmass companions that were detected through perturbations to the smooth and symmetric light curves produced by
the primary, the companion was discovered through the channel of a repeating event, in which the companion itself produced its own single-mass light curve after the event produced by the primary had ended. Thanks to the
continuous coverage of the second peak by high-cadence surveys, the possibility of the repeating nature due to source binarity is excluded with a 96% confidence level. The mass of the companion estimated by a Bayesian
analysis is Mp 4.1 2.5 M 6.5 = - J + . The projected primary-companion separation is a 6.5 1.9 = 1.3 ^ - + au. The ratio of the separation to the snow-line distance of a^ asl ~ 15.4 corresponds to the region beyond Neptune, the outermost
planet of the solar system. We discuss the importance of high-cadence surveys in expanding the range of microlensing detections of low-mass companions and future space-based microlensing surveys.