A nightcore edit is a remix track that speeds up!
A nightcore edit is a remix track that speeds up its source material, increasing its pitch. Formed in 2002, the name for the internet-based genre was originally defined as sped-up and pitch-shifted versions of trance and eurodance songs, but its definition expanded into non-dance territory by the time the remix style became popular in the 2010s. When uploaded as a music video on YouTube, most nightcore videos feature a manga or anime picture as a visual component.
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 genre.