Optical frequency combs, with their multitude of perfectly equidistant laser lines, have revolutionized the fields of metrology and high-resolution spectroscopy, and have proven to be enabling elements in a variety of applications. In our work, published on Physical Review Letters and selected as Editor’s Suggestion, we show a new way to generate optical frequency combs, by shining a single frequency laser in an optical parametric oscillator, and reveal an entirely new emission feature of an apparently well assessed optical device. In our case, we were able to simultaneously generate a comb of hundreds of equally spaced frequencies around twice the pump laser wavelength. This result is supported by a new theoretical model, which discloses an entirely new landscape of OPO dynamics, never observed till now. The quality and stability of the obtained combs are extremely promising for demanding applications of frequency combs, and our findings open a new conceptual route to straightforward and more efficient techniques for comb synthesis. In particular they can be extendible to the generation of frequency combs in the elusive mid-infrared region, where existing solutions are still complex.