Fourth-order perturbation theory is used to derive the Dysthe (“DISS-tuh”) equation, which describes the generation of these phenomena. Optical analogs of these phenomena are generated by inputting a laser frequency comb near a supercontinuum generation threshold. These phenomena may develop from amplification of a solution to the nonlinear (-5[2])Schrödinger equation called the Peregrine breather. The Benjamin–Feir, or “modulational,” instability is used to explain the formation of these phenomena. (-5[1])A laser rangefinder on the (*) Draupner platform (10[1])was used to record the first observed one of these phenomena in 1995. These phenomena have a crest-to-trough distance that is at least double the significant wave height. For 10 points, name these (10[1])unexpectedly (10[1]-5[1])large ocean waves. (10[1])■END■ (10[5])