A nightcore edit is a remix track that speeds up its source material by 20% and increases its pitch. Formed in 2002, the name for the internet-based music was originally defined as sped-up and pitch-shifted versions of trance, techno and eurodance songs, but its definition expanded into non-dance territory by the time the remix style became popular in the 2010s. The type of music that started as a subgenre of trance is still considered so by many people. Indeed, dedicated trance fans usually call it “happy nightcore” to indicate its “similar-but-different” nature. Nightcore is characterized by a sped-up melody (sometimes), fast rhythmic beat (usually), and higher than normal pitch. Almost all nightcore music are original songs nightcored (remixed into nightcore) by nightcore fans.
The publicity of nightcore has also been attributed to the works of PC Music, formed in 2013 by musicians Danny L Harle and A. G. Cook who claimed to be influenced by the music.