Arms of the Sea
Also known as a sleeper wave or a king wave, sneaker waves are a disproportionately large coastal wave that can sometimes appear in a wave train without warning.
The unpredictability of sneaker waves and their tendency to arrive suddenly after lengthy periods of gentle, lapping waves makes it easy for them to surprise unwary or inexperienced beachgoers. Because they are much larger than preceding waves, sneaker waves can catch inattentive swimmers, waders, and other people on beaches and ocean jetties and wash them into the sea.