Without a doubt the video of 2012—racking up close to a billion views on YouTube since it was posted in July—“Gangnam Style” features PSY riding an invisible horse through the streets of Seoul’s Gangnam district. The catchy song paired with social satire and tongue-in-cheek vibe has spread so quickly it reminds us why videos are called viral. The video has not only doubled the value of Psy’s father’s company but has sparked an (occasionally lethal) dance craze, aptly called “the invisible horse,” and catapulted PSY (a.k.a. Jae-Sang Park, a South Korean performer and reality TV judge) to international super stardom. It has even hatched its own cottage industry of mash-ups and imitators with groups as diverse as political candidates, Eton students, prisoners, Navy midshipmen and Chinese dissident artist Ai Wei Wei.