Harlem Shake
The 2013 video format where one person dances alone among people ignoring them, until the bass drops and everyone is suddenly doing the same thing in costume.
The template was exactly thirty seconds long, required no talent and could be filmed over a lunch break, which explains why every office, school class and military unit on the planet made one during February that year. At the peak, thousands of versions were uploaded a day. The genuinely interesting part is the economics behind it: Billboard had just started counting YouTube streams in its charts, which sent Baauer's track to number one on the Hot 100 driven almost entirely by the meme. It was the first time a meme directly produced a chart-topper. The dance, incidentally, has nothing to do with the actual Harlem shake from the 1980s, as people in Harlem pointed out without much success.