Harlem Shake was released by American producer Baauer in 2012 as an electronic trap track, but it exploded in February 2013 when short YouTube videos turned its drop into a repeatable format. One person would dance alone during the build while others acted unaware, then the cut on the drop showed the whole group dancing wildly, often in costumes. Thousands of versions from offices, sports teams and military units followed, pushing the song to number one in several countries and making the format one of the defining early viral video trends.